Title: Animal Diversity
Course: Question Banks

Q: It is generally believed that the earliest animals evolved from ________.
- bacteria (Incorrect. Bacteria are not thought to be the direct ancestors of early animal life.)
- archaea (Incorrect. Archaea are not thought to be the direct ancestors of early animal life.)
- protists (Correct. Early animal life most likely evolved from protists resembling the modern day choanoflagellates.)
A: protists

Q: Most scientists generally hold that animal life appeared during the ________ period, though recent discoveries are challenging that understanding.
- Cryogenain (Incorrect. There is increasing evidence that early animal life may have evolved during the Cryogenain period but this is not the most widely accepted theory.)
- Cambrian (Incorrect. Animal life was well established by the Cambrian period of the Paleozoic Era.)
- Ediacaran (Correct. The most widely accepted theory has animal life evolving during the Ediacaran period at the end of the Proterozoic Era.)
A: Ediacaran

Q: The oldest animals with hard body parts were recently discovered in ________.
- South Africa (Incorrect. The oldest animals with hard body parts were not recently discovered in South Africa.)
- South America (Incorrect. The oldest animals with hard body parts were not recently discovered in South America.)
- South Australia (Correct. These sponge-like fossils date to approximately 560 million years ago.)
A: South Australia

Q: Most of the animal phyla in existence today appeared during the ________ explosion.
- Cryogenain (Incorrect. There is increasing evidence that early animal life may have evolved during the Cryogenain period but this period was not known for rapid evolution of animals.)
- Ediacaran (Incorrect. The most widely accepted theory has animal life evolving during the Ediacaran period at the end of the Proterozoic Era, but not rapidly evolving into diverse phyla.)
- Cambrian (Correct. Animal life and diversity rapidly evolved during the Cambrian period, giving rise to the term “Cambrian explosion.”)
A: Cambrian

Q: A dominant species during the Cambrian period was the ________.
- horseshoe crab (Incorrect. Horseshoe crabs are morphologically similar to this dominant species.)
- troglodytes (Incorrect. Troglodyte means “cave dweller” and refers to either extinct humans or solitary human hermits.)
- trilobite (Correct. Trilobites are extinct arthropods that thrived during the Cambrian period.)
A: trilobite

Q: The change in atmospheric oxygen concentrations is one possible factor that contributed to the ________.
- end-Permian mass extinction that wiped out 95 percent of the extant species on Earth (Incorrect. Changes in atmospheric oxygen did not contribute to a mass extinction event during the Permian.)
- rise of the dinosaurs at the beginning of the Triassic period (Incorrect. Changes in atmospheric oxygen did not contribute to the rise of dinosaurs in the Triassic period.)
- sharp increase in animal diversity during the Cambrian period (Correct. Rising atmospheric oxygen, along with increases in oceanic calcium concentrations, may have preceded and facilitated the Cambrian explosion.)
A: sharp increase in animal diversity during the Cambrian period

Q: ________ first appeared on land shortly after the Cambrian period.
- Animals (Incorrect. Plant life had to colonize the land before animals could leave the water for terrestrial life.)
- Insects (Incorrect. Insects are simply a type of animal.)
- Plants (Correct. Plant life had to colonize the land before animals could leave the water for terrestrial life.)
A: Plants

Q: A ________ is the devastating and rapid loss of genetic diversity.
- bottleneck (Incorrect. A bottleneck is a localized reduction in genetic diversity (at the level of a population).)
- collapse (Incorrect. The term “collapse” is not used to refer to this phenomenon in evolutionary history.)
- mass extinction (Correct. The key with mass extinctions is they involve a number of different species, sometimes even entire phyla.)
A: mass extinction

Q: The largest mass extinction occurred at the end of the ________ period, and facilitated the rise of the dinosaurs.
- Triassic (Incorrect. A mass extinction did occur at the end of the Triassic period but this is not the largest in prehistory.)
- Cretaceous (Incorrect. The end-Cretaceous mass extinction wiped out the dinosaurs.)
- Permian (Correct. The end-Permian mass extinction wiped out 95 percent of the extant species on Earth. Dinosaurs rose to dominate the planet afterwards.)
A: Permian

Q: Animals are primarily classified based on ________.
- genetic and biochemical markers (Incorrect. While modern genetic and biochemical studies may modify classifications, the majority of animals are not classified using these features.)
- genetic and developmental features (Incorrect. Animal classifications are not based on these features overall.)
- morphological and developmental features (Correct. Animal classification is largely based on morphological and developmental features such as body plans.)
A: morphological and developmental features

Q: Animals with three germ layers are further characterized by the presence or absence of a ________.
- vertebral column (Incorrect. This is a more granular layer of characterization that occurs at a lower taxonomic layer.)
- mesoderm (Incorrect. This is the third germ layers, so is involved in classifying animals based on two versus three germ layers.)
- coelom (Correct. The presence or absence of a coelom is the next feature used to characterize animals after the number of germ tissue layers.)
A: coelom

Q: All animals are ________.
- eumetazoans (Incorrect. This term means “true animal”; there are actually animals that do not fall into this group.)
- macroscopic (Incorrect. There are a number of microscopic animals, including arthropods and crustaceans.)
- metazoans (Correct. Another term for animal is metazoa.)
A: metazoans

Q: The most basic division of animals is based on whether or not they have ________.
- body symmetry (Incorrect. Body symmetry is inherent in the feature that is used to divide animals into “true” versus “beside” animals. But the type of symmetry is used to divide animals after the most basic distinction.)
- two or three germ layers (Incorrect. This level of classification is not the most basic dividing line in the animal kingdom.)
- specialized tissues (Correct. Eumetazoa, or “true animals,” all have specialized tissues. Parazoa, or “beside the animals,” have no tissues. These are the sponges.)
A: specialized tissues

Q: The ________ contain cells that strongly resemble the protist ancestor of animals.
- comb jellies (Incorrect. Comb jellies do not include choanoflagellate-like cells.)
- cnidarians (Incorrect. Cnidarians do not include choanoflagellate-like cells.)
- sponges (Correct. The choanocyte cells of sponges resemble the choanoflagellate protists thought to closely resemble the animal ancestor.)
A: sponges

Q: True animals are next divided into clades based on ________.
- specialized tissues (Incorrect. Eumetazoa, or “true animals,” all have specialized tissues. Parazoa, or “beside the animals,” have no tissues. These are the sponges.)
- two or three germ layers (Incorrect. This level of classification is not the first used on the true animals.)
- body symmetry (Correct. Body symmetry is inherent in having tissues, but it may be radial symmetry or bilateral symmetry, the next characteristic used to group animals.)
A: body symmetry

Q: Modern phylogenetics is influenced by ________ analyses.
- morphological (Incorrect. Morphological data built previous phylogenetic trees that are being actively refined with modern tools.)
- more powerful microscopic (Incorrect. More powerful microscopes are available today but they are not used as a stand-alone tool in phylogenetics.)
- nucleic acid and protein (Correct. Modern phylogenetics is rewriting animal classification, using nucleic acid and protein based data.)
A: nucleic acid and protein

Q: rRNA data has reclassified the ________ as a type of protostome.
- annelids (Incorrect. Annelids were always considered protostomes.)
- ecdysozoans (Incorrect. This clade was always composed of animals considered protostomes.)
- lophophorates (Correct. Previously these animals were considered primitive deuterostomes but now are thought to be protostomes.)
A: lophophorates

Q: The ________ may be living species of some of the earliest bilaterians.
- nematodes (Incorrect. Nematodes are not considered to be representative of the earliest bilaterians.)
- bryozoans (Incorrect. The bryozoans are not considered to be representative of the earliest bilaterians.)
- acoelmorphians (Correct. Modern evidence indicates these acoel flatworms may not be flatworms but rather are living representatives of some of the earliest divergent bilaterians.)
A: acoelmorphians

Q: Radially symmetrical animals have ________.
- a right and left side (Incorrect. Right and left sides are associated with bilateral symmetry.)
- no central axis (Incorrect. Only the asymmetric Parazoa lack a central axis.)
- a top and bottom (Correct. Radially symmetrical animals have a top and bottom surface, also known as the oral side and aboral side.)
A: a top and bottom

Q: The ________ change from bilateral to radial symmetry over the course of their life cycles.
- Parazoa (Incorrect. Sponges are always asymmetrical.)
- Ctenophora (Incorrect. Comb jellies are always radially symmetrical.)
- Echinodermata (Correct. The sea stars, sand dollars, and sea urchins will change from bilateral larvae to radially symmetrical adults.)
A: Echinodermata

Q: A ________ plane divides a bilateral animal into equal right and left halves.
- frontal (Incorrect. A frontal plane will divide an animal into front and back halves, which are often not equal.)
- transverse (Incorrect. A transverse plane will divide an animal into upper and lower portions; these are often not equal.)
- midsagittal (Correct. A midsagittal plane will divide an animal directly in the middle into equal right and left halves.)
A: midsagittal

Q: Aquatic bilateral animals often have a ________ shape to reduce drag.
- thin (Incorrect. An overall thin shape will not reduce drag.)
- reniform (Incorrect. A kidney-shaped body will not reduce drag.)
- fusiform (Correct. A tubular body tapered at both ends reduces drag on the body as it moves through the water.)
A: fusiform

Q: Most animals have a ________.
- cartilaginous skeleton (Incorrect. Few animals have a skeleton composed of cartilage, mainly just skates, rays, and sharks.)
- endoskeleton (Incorrect. An internal skeleton, composed of bone or cartilage, is not the most common skeletal type in animals.)
- exoskeleton (Correct. Most animals, including insects, arthropods, arachnids, and others, have a hard covering or shell that protects and provides attachments for muscles.)
A: exoskeleton

Q: The larger the size of an sphere, the ________ it has.
- less volume (Incorrect. Volume will increase as size increases.)
- more surface-to-volume (Incorrect. Surface-to-volume ratio will decrease as a sphere becomes larger. As a result, organisms must become multicellular in order to be larger past a certain size (microscopic).)
- less surface area (Correct. Reduced surface area slows diffusion. As a result, organisms must become multicellular in order to be larger past a certain size (microscopic).)
A: less surface area

Q: Animals that conserve heat to maintain a relatively stable body temperature are ________.
- ectotherms (Incorrect. Ectotherms are dependent on the environment for body heat.)
- heterotherms (Incorrect. Heterotherms are animals that can change between ectothermic and endothermic strategies based on fluctuations in metabolic rates. This term is not often used as these animals are truly endotherms that can reduce their metabolism drastically.)
- endotherms (Correct. Endotherms conserve the waste energy from metabolism as body heat to maintain a steady temperature.)
A: endotherms

Q: ________ have a higher basal metabolic rate per body weight.
- Male animals (Incorrect. Higher BMRs are not necessarily based on sex.)
- Larger animals (Incorrect. Per body weight, larger animals do not have a higher BMR.)
- Smaller animals (Correct. Due to a greater surface area for mass, smaller animals lose heat at a faster rate to the environment. Therefore, they have a higher basal metabolic rate per body weight.)
A: Smaller animals

Q: ________ occurs in the summer months, while ________ occurs in the winter.
- Hibernation; torpor (Incorrect. Hibernation does not occur in the summer months.)
- Dormancy; hibernation (Incorrect. Dormancy is an ectothermic response to cold weather, so is the equivalent of hibernation in endotherms.)
- Estivation; hibernation (Correct. Estivation is a decrease in activity and metabolism in response to high temperatures and little water, while hibernation is the same in response to cold.)
A: Estivation; hibernation

Q: Coordination of motility in animals requires ________ tissues.
- epithelial and connective (Incorrect. Neither of these tissue is involved in coordination of movement.)
- bone and circulatory (Incorrect. Neither of these tissue is required for coordinated movement.)
- nerve and muscle (Correct. Both nerve tissue and muscle tissue are required for coordination of motility.)
A: nerve and muscle

Q: Animal diversity is so extensive because of ________.
- multicellularity (Incorrect. Plants are equally multicellular but not as diverse as animals.)
- redundancy and pluripotency of cells (Incorrect. These characteristics are not responsible for the abundance in animal diversity.)
- differentiation and specialization of tissues (Correct. The diversity and speciality of animal tissues allows for the incredible diversity in this kingdom.)
A: differentiation and specialization of tissues

Q: ________ have specialized cells, but these cells are not organized into tissues.
- Plants (Incorrect. Plants do have specialized tissues.)
- Eumetazoa (Incorrect. Eumetazoa, or “true animals,” are characterized by their specialized tissues.)
- Parazoa (Correct. The simple sponges have specialized cells but no tissues, unlike the rest of the animals.)
A: Parazoa

Q: ________ epithelial cells fit together to form a covering or lining.
- Cuboidal (Incorrect. These cube-shaped cells are normally present in glands where they secrete material.)
- Transitional (Incorrect. These round, simple cells appear only in the urinary system.)
- Squamous (Correct. These flat, irregularly round cells are coverings such as skin or linings such as those protecting the mouth.)
A: Squamous

Q: Multi-layered epithelial tissue is said to be ________.
- cuboidal (Incorrect. Cuboidal refers to the shape of individual cells, not the number of layers (or lack of layers) in an epithelial tissue.)
- simple (Incorrect. Simple epithelial tissue is composed of only a single layer of cells.)
- stratified (Correct. Stratified epithelial tissue is composed of multiple layers of cells.)
A: stratified

Q: ________ epithelial cells form a layer that unfolds and expands to hold a larger volume.
- Squamous (Incorrect. These flat, irregularly round cells are coverings such as skin or linings such as those protecting the mouth.)
- Cuboidal (Incorrect. These cube-shaped cells are normally present in glands where they secrete material.)
- Transitional (Correct. These round, simple cells appear only in the urinary system, primarily in the bladder and ureter.)
A: Transitional

Q: ________ fibers provide strength to connective tissues.
- Reticular (Incorrect. These fibers provide support to connective tissues and associated organs.)
- Elastic (Incorrect. These fibers provide flexibility.)
- Collagen (Correct. These fibers provide strength to connective tissues, preventing it from being torn or separated from surrounding tissues.)
A: Collagen

Q: ________ connective tissue is found in locations that are stressed from all directions, such as tendons or dermis.
- Areolar (Incorrect. Areolar tissue cannot be stressed from all sides.)
- Osseous (Incorrect. Osseous tissue is not found in locations that experience stress from all sides.)
- Fibrous (Correct. Fibrous connective tissue is designed to experience and handle stress from all sides.)
A: Fibrous

Q: ________ connective tissue has a consistency similar to a cotton ball pulled apart, in keeping with its role in holding vessels and organs in place.
- Fibrous (Incorrect. Irregular fibrous connective tissue makes up the dermis, while regular fibrous connective tissue makes up tendons and ligaments.)
- Adipose (Incorrect. Adipose, or fat tissue, is composed of adipocytes that store fat for energy metabolism.)
- Areolar (Correct. Also known as loose connective tissue, this is found around blood vessels and body organs.)
A: Areolar

Q: ________ muscle is the only type of muscle that is under voluntary control.
- Cardiac (Incorrect. Cardiac muscle is not under voluntary control; it must keep the heart beating.)
- Smooth (Incorrect. Smooth muscle is not under voluntary control; it composes the walls of blood vessels, digestive tract, and reproductive tract.)
- Skeletal (Correct. Skeletal muscles move bones and are under voluntary control.)
A: Skeletal

Q: Smooth muscle is a component of ________.
- skeletal muscles (Incorrect. There is no smooth muscle in skeletal muscles.)
- heart (Incorrect. Cardiac muscle makes up the heart.)
- visceral organs (Correct. Smooth muscle composes the walls of blood vessels, digestive tract, and reproductive tract.)
A: visceral organs

Q: ________ muscle is composed of cells with a single, centrally located nucleus and has striations.
- Smooth (Incorrect. Smooth muscle is composed of cells with a single, centrally located nucleus but it does not have striations.)
- Skeletal (Incorrect. Skeletal muscles are striated tissues with multinucleated cells with peripheral nuclei.)
- Cardiac (Correct. Cardiac muscle makes up the heart and is composed of striated fibers of cells with a single, central nucleus.)
A: Cardiac

Q: Nervous tissue is specialized to send and receive ________.
- chemical signals (Incorrect. Chemical messengers do have a role in nerve impulses, but many tissues send and receive chemical signals.)
- gravitational signals (Incorrect. Animal tissues are not generally specialized to respond to gravity’s signals.)
- electrical signals (Correct. Nerve tissues send and receive electrical impulses.)
A: electrical signals

Q: The ________ of a neuron receive signals.
- axon (Incorrect. Axons send signals.)
- astrocytes (Incorrect. Astrocytes are a type of glial cell that insulate axons to facilitate conduction of the electrical signal.)
- dendrites (Correct. Dendrites project from neurons and receive signals.)
A: dendrites

Q: A nerve is composed of ________.
- an axon and a dendrite (Incorrect. These make up a neuron, but not a nerve.)
- a dendrite and an astrocyte (Incorrect. These may be parts of the nerve, but is not a complete answer.)
- neuron and glial cells (Correct. A nerve must contain a neuron and the associated supportive glial cells.)
A: neuron and glial cells

Q: Some insects and vertebrates can reproduce asexually by ________.
- budding (Incorrect. Budding is the most common form of asexual reproduction for stationary aquatic animals.)
- fragmentation (Incorrect. Fragmentation is another common form of asexual reproduction for stationary aquatic animals.)
- parthenogenesis (Correct. Unfertilized eggs of some insects and a few vertebrates may develop into new male offspring to ensure genetic propagation.)
A: parthenogenesis

Q: Animals that undergo ________ metamorphosis appear quite different in larval and adult forms.
- incomplete (Incorrect. In incomplete morphogenesis, the young resemble the adult form of the animal.)
- transformational (Incorrect. There is no “transformational” metamorphosis.)
- complete (Correct. Complete metamorphosis involves larval forms that differ quite a bit from the adult form.)
A: complete

Q: The germ layers arise during the ________ stage of embryonic development.
- blastula (Incorrect. During the blastula stage, the zygote is formed into a hollow ball.)
- cleavage (Incorrect. This first stage of embryonic development is simply cell division to generate an eight-celled structure.)
- gastrula (Correct. Germ layers are formed during gastrulation, the third stage of embryonic development.)
A: gastrula

Q: The ________ gives rise to the muscle tissues, connective tissues, and most visceral organs.
- endoderm (Incorrect. The endoderm predominantly generates the lining of the digestive tract and the lining of the respiratory tract.)
- ectoderm (Incorrect. The ectoderm develops into the outer epithelial covering and the central nervous system predominantly.)
- mesoderm (Correct. This third germ layer, not present in animals with radial symmetry, gives rise to all muscles, the skeleton and blood cells, and most other visceral organs.)
A: mesoderm

Q: The ________ have a mesoderm region completely filled with tissue.
- pseudocoelomates (Incorrect. The pseudocoelomates have a pseudocoelom derived from mesoderm and endoderm.)
- eucoelomates (Incorrect. Animals with a true coelom have an internal body cavity derived entirely from mesoderm.)
- acoelomates (Correct. The acoelomates do not develop a coelom; hence their mesoderm is completely filled with tissue.)
A: acoelomates

Q: Protostomes undergo ________ cleavage patterns.
- spiral complete (Incorrect. There is no complete cleavage pattern.)
- radial indeterminate (Incorrect. Deuterostomes undergo radial, indeterminate cleavages during embryonic development.)
- spiral determinate (Correct. Protostomes undergo spiral, determinate cleavages during embryonic development.)
A: spiral determinate

Q: Hox genes are responsible for determining the ________ of animals.
- lifespan (Incorrect. To date, no genes have been concretely connected to lifespan.)
- developmental timing (Incorrect. Developmental timing is not controlled by the Hox genes.)
- general body plan (Correct. Hox genes determine the general and overall body plan, such as number of body segments and head-tail directionality.)
A: general body plan

Q: In vertebrates there are ________ clusters of Hox genes.
- two (Incorrect. There are not two Hox gene clusters in vertebrates.)
- six (Incorrect. There are not six Hox gene clusters in vertebrates.)
- four (Correct. In vertebrates, there is the Hox-A, Hox-B, Hox-C, and Hox-D clusters.)
A: four

Q: Hox genes are ________ that regulate expression of a number of other genes.
- activators (Incorrect. Hox genes are not necessarily activators.)
- proto-oncogenes (Incorrect. Hox genes are not proto-oncogenes.)
- master control genes (Correct. These genes code transcription factors that control the expression of numerous other genes.)
A: master control genes

Q: Homeostasis balances the internal environment of the body to stay at or near the ________.
- Goldilocks zone (Incorrect. This is actually an astronomy term for galactic regions that may have Earth-like planets.)
- effector (Incorrect. The effector is the mechanism that responds to the commands of the control center to achieve homeostasis.)
- set point (Correct. Adjustments must be made to keep the body regulated at or near a specific value for some aspect of the body or cells.)
A: set point

Q: The ________ is often the control center in animals that receives and processes environmental signals.
- heart (Incorrect. The heart is not generally the control center in animals.)
- endocrine system (Incorrect. The endocrine system is not generally the control center in animals.)
- brain (Correct. The brain is usually the control center in animals that determines the appropriate response to environmental signals.)
A: brain

Q: Physiological systems within the body are adjusted by ________.
- negative feedback loops (Incorrect. Negative feedback loops may play a role in body adjustments in some cases, but this is not the overall approach.)
- receptor-mediated regulation (Incorrect. This is not the correct term for how the body maintains homeostasis.)
- homeostatic regulation (Correct. Adjustments are made in response to changes in the environment in order to maintain a constant and balanced internal environment.)
A: homeostatic regulation

Q: A homeostatic response that changes the direction of a stimulus is a ________.
- positive feedback loop (Incorrect. A positive feedback loop continues the direction of a stimulus.)
- downregulation (Incorrect. Not all homeostatic responses of this nature result in “down”-regulation.)
- negative feedback loop (Correct. The stimulus is not allowed to continue as it did before the receptor sensed it in this type of homeostatic response.)
A: negative feedback loop

Q: Blood clotting is one of the few ________ that exists in animal bodies.
- downregulations (Incorrect. This is not what blood clotting represents..)
- negative feedback loops (Incorrect. Blood clotting is not a negative feedback loop.)
- positive feedback loops (Correct. A positive feedback loop continues the direction of a stimulus; in the case of blood clotting, once one clotting factor is activated, it triggers activation of the next and so on.)
A: positive feedback loops

Q: ________ occurs when changes are made in one body system to maintain set point in a different body system.
- Alteration (Incorrect. Alteration involves shifting the set point for a body system.)
- Activation (Incorrect. Activation is not a term used in homeostatic regulation.)
- Acclimatization (Correct. Acclimatization involves homeostatic regulation that utilizes changes in one system to maintain a different system’s set point.)
A: Acclimatization

Q: Due to the impact of heat on ________, it is essential for organisms to have some form of thermoregulation.
- nucleic acids (Incorrect. Nucleic acids are not as sensitive to heat changes as some other macromolecules.)
- fats (Incorrect. Fats are not as sensitive to heat changes as some other macromolecules.)
- proteins (Correct. Proteins, especially enzymes, are quite sensitive to temperature changes. Enzyme activity levels rise sharply with temperature increases, and all proteins denature quickly under high heat.)
A: proteins

Q: In advanced animals, homeostasis and ________ are centered in the hypothalamus.
- acclimatization (Incorrect. Acclimatization is not centered in the hypothalamus.)
- alteration (Incorrect. Alteration is not centered in the hypothalamus.)
- temperature control (Correct. In higher animals, the hypothalamus controls homeostasis and temperature regulation.)
A: temperature control

Q: A ________ is a normal defense mechanism meant to combat pathogen infection in a variety of ways.
- snotty nose (Incorrect. A snotty nose is not a defense mechanism combating pathogens.)
- blister (Incorrect. A blister is not a defense mechanism combating pathogens.)
- fever (Correct. Fevers are now understood to be a response to infection, not a complication of infection.)
A: fever

Q: ________ utilize internal energy sources to control their body temperature.
- Ectotherms (Incorrect. Ectotherms rely on external energy to dictate their body temperature.)
- Poikilotherms (Incorrect. Poikilotherms have constantly fluctuating body temperatures; this term does not specify the energy source that drives those fluctuations, though usually it is external environment.)
- Endotherms (Correct. Endotherms control their body temperature using internal energy sources.)
A: Endotherms

Q: Heat can be removed using liquid during the process of ________.
- convection (Incorrect. Convection is the process of dissipating heat using air on a surface.)
- conduction (Incorrect. Conduction is the direct transfer of heat between objects through physical contact.)
- evaporation (Correct. Evaporation is the process of dissipating heat using water on a surface.)
A: evaporation

Q: Endotherms use their ________ to help maintain body temperature.
- fur (Incorrect. Not all endotherms have fur, though those with fur use it to conserve body heat.)
- behavior (Incorrect. Ectotherms utilize behavioral changes to regulate their body temperature.)
- circulatory system (Correct. Changes in the circulatory system may conserve or dissipate heat, depending on an endotherm’s specific need.)
A: circulatory system