is cold-blooded
	is warm-blooded
	obtains most of its heat from its environment
	can generate enough metabolic heat to keep its body temperature above that of its surroundings
	has a body temperature that varies considerably

	a warm-blooded animal
	a cold-blooded animal
	an animal that gets most of its body heat from its metabolism
	an animal that temporarily abandons warm-bloodedness
	an animal that regulates its body temperature by its behavior

	all animals
	amphibians and reptiles
	arthropods
	reptiles, birds, and mammals
	birds and mammals

	can be prevented by drinking adequate amounts of water
	happens only on hot days
	is dangerous because it causes extreme loss of sodium and chloride ions
	helps the body thermoregulate
	heavily causes irreversible dehydration

	interferes with heat loss by conduction
	holds warm water vapor
	interferes with heat loss by evaporative cooling
	prevents countercurrent heat exchange from occurring
	increases metabolic heat production

	his body heat evaporated away into the rock
	he lost heat through conduction from his gaping jaws
	receiving heat by conduction from the sun
	heat was conducted away by the gentle breeze
	heat radiated from his tired body

	dilate, allowing blood to keep the skin warm
	constrict, forcing blood to flow through vessels in the skin
	constrict, reducing heat loss from blood at the surface
	dilate, causing blood to pass through the cold skin more quickly
	dilate, preventing blood flow to the surface

	An elephant rolls in the mud and sprays dust over its back.
	A marine iguana dives into the surf after sunning on a rock.
	A man puts on a wide-brimmed hat while laboring in the sunshine.
	A falcon migrates from San Francisco to Brazil for the winter.
	Sweat oozes from the hide of a thirsty antelope in the drought-stricken Serengeti plains.

	inversion
	sleep
	torpor
	lymphoma
	oxytocin

	expend considerable energy in matching concentrations of their body fluids with those of their marine environment
	rely on the digestive, respiratory, and excretory systems to remove excess salts and water from their bodies
	have an internal environment isotonic with their external environment, which does not require expending energy
	spontaneously absorb water through the body surface and lose solutes in urine
	spontaneously lose water through body surfaces and must actively unload ions and drink water to maintain osmotic homeostasis

	osmoregulators that do not exchange quantities of water by osmosis with the environment
	likely to have problems with osmoregulation similar to those of freshwater fish
	either arthropods or vertebrates
	obligated to protect their eggs from drying with water-resistant shells
	usually nocturnal

	Because they live in a hypotonic solution, their cells take up an excess of water that must be excreted.
	Because they live in a hypotonic solution, their cells tend to accumulate a lot of solute that must be excreted.
	Because they live in a hypertonic solution, their cells take up an excess of water that must be excreted.
	Because they live in a hypertonic solution, their cells tend to accumulate a lot of solute that must be excreted.
	Because animals must live in an isotonic solution, they excrete solutes to make the concentration of solutes in the water equal to the concentration of solutes in their cells.

	experience no net water loss by osmosis
	experience significant water gain by osmosis
	experience significant water loss by osmosis
	do not need to expend energy on the active transport of solutes from their bodies to the environment
	do not exist

	They have different diets.
	Land animals can get the energy needed to make urea or uric acid.
	Ammonia is very toxic, and it takes lots of water to dilute it.
	Land animals cannot afford the energy needed to make ammonia.
	Fish need to get rid of ammonia, but land animals need it to live.

	uric acid
	amino acids
	ammonia
	urea
	nitrite

	drug use
	consumption of foods high in nitrates, such as green vegetables
	protein metabolism
	the body's attempts to maintain pH homeostasis
	metabolism of fatty foods

	is synthesized in the kidneys from ammonia and CO2
	forms solids that are relatively insoluble and nontoxic
	readily decomposes on exposure to air
	is readily excreted through feathers and scales
	can be recycled and utilized as an additional energy source

	The liver filters out toxins such as alcohol and drugs.
	The liver makes fat digestion possible by producing bile.
	The liver removes and converts toxic ammonia into urea.
	The liver has the metabolic machinery to chemically treat a great number of substances.
	The liver stabilizes glucose levels in the blood.

	loop of Henle
	ureter
	urethra
	uvula
	none of these

	filter the blood and capture the filtrate
	reabsorb water into the blood
	break down harmful toxins and poisons
	reabsorb salts and nutrients
	refine and concentrate the urine for excretion

	elimination of nitrogenous wastes
	maintenance of the salt balance
	elimination of undigested foods
	maintenance of the water balance
	production of urine

	Bowman's capsule
	collecting duct
	glomerulus
	loop of Henle
	proximal tubule

	neurons
	glomeruli
	ureters
	nephrons
	collecting ducts

	water
	plasma proteins
	urea
	glucose
	sodium

	ammonia because it uses less energy to make than uric acid or urea
	urea because it is less toxic than uric acid
	uric acid because it takes less energy to make than urea
	uric acid because it does not require water for excretion
	ammonia because it is the most soluble of all the nitrogen-containing metabolic waste products

	breaking down body wastes
	excreting wastes
	regulating body fluid composition
	filtering the blood
	producing urine

	such as the tardigrade is lethal
	is a problem because carbohydrates are fragile and break down when they dry out
	has nothing in common with freezing
	is a problem because fluid mosaic cell membranes fall apart when deprived of water
	may be less damaging in the presence of sugar

	filtration of plasma
	reabsorption of water into the blood
	breakdown of harmful toxins and poisons
	reabsorption of salts and nutrients
	production and release of ADH

	filtration and secretion
	reabsorption and secretion
	reabsorption and excretion
	filtration and reabsorption
	secretion and excretion

	Filtration happens when water, nitrogenous waste, and valuable solutes are forced from the blood into the nephron's proximal tubule.
	Reabsorption is the recovery process that returns valuable solutes and water to the capillaries from the nephron so they are not wasted in the urine.
	Secretion transports certain toxins, drugs, and excessive ions from the capillaries to the filtrate.
	Excretion moves urine, the processed filtrate, out of the kidney, through the ureter, the bladder, and finally out of the body via the urethra.
	Reabsorption is the process where toxins, drugs, and excessive ions that remain in the blood after filtration are transported into the nephron for disposal in the urine.

	secretion
	filtration
	blood cell formation
	cellular respiration
	reabsorption

	excrete the maximum amount of salt
	neutralize toxins that might accumulate in the kidney
	control the pH of the interstitial fluid
	excrete a large amount of water
	reabsorb water

	water
	red blood cells
	H+ ions
	amino acids
	urea

	It provides water for reabsorption by the interstitial fluid and capillaries.
	It loses urea to the renal medulla, helping this tissue to maintain its concentration gradient of solutes.
	It absorbs some drugs and poisons from surrounding capillaries.
	It helps maintain the concentration gradient of NaCl in the interstitial fluid, thus increasing water reabsorption.
	It collects processed filtrate from the nephrons.

	In increased concentrations ADH causes nephrons to absorb water faster.
	In higher concentrations ADH causes more water to be released from the nephrons to be reabsorbed by the blood.
	Low levels or the absence of ADH in the blood are the brain's response to thirst.
	ADH is the only hormone that provides a system of control over the kidney as an osmoregulator for urine production.
	ADH controls the rate that filtrate moves from the glomerulus into Bowman's capsule.

	the kangaroo rat is adapted to living in an environment where water is scarce
	the white rat's diet is much less varied than the kangaroo rat's
	the kangaroo rat cannot always find food
	the kangaroo rat produces more body wastes
	the kangaroo rat has less stress and lower blood pressure

	Bowman's capsule is a network of capillaries inside the glomerulus.
	The proximal tubule is the portion of the nephron tubule farthest from Bowman's capsule.
	The renal cortex, which contains the nephrons, is interior to the renal medulla.
	The collecting duct of a nephron is parallel to the loop of Henle in the renal medulla.
	The distal tubule of a nephron connects with the renal pelvis of the kidney via the ureter.

	blood capillaries
	urine
	lymphatic fluid
	cells of the kidney
	the loop of Henle

	a lower solute concentration than blood contains
	a higher concentration of urea than blood contains
	a lower glucose concentration than blood contains
	a lower concentration of urea than blood contains
	a much smaller volume of fluid than the blood passing through it

	used dialyzing solution
	fresh dialyzing solution
	tubing made of selectively permeable membrane
	dialyzing solution bathing the tubing
	pump