Animals in desert biomes
o must have thick fur to survive the cold nights
o only come out during the day, when temperatures are warm
O have special adaptations to survive the extreme climate
suvive by eating cereal grasses, like wheat and barley

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

Hormones are chemical molecules produced by endocrine glands. one such endocrine gland is the thyroid gland, which synthesizes the thyroid hormone, which in turn affects the heart muscles. which two statements describe the probable reason for the function of the hormone? the cells in the heart have specific receptors that allow for the intake of hormones. the heart and the endocrine glands have the exact same types of cells. all cells make the same types of hormones. thyroid hormones show their effect on the heart by means of specialized cells. thyroid cells and cardiac cells have different dna.

Select the correct answer. which of the following statements is a scientific claim? a. the early solar system had large amounts of water; so, the oldest objects in the solar system should also be abundant in water. b. the mass of the universe is much greater than current models predict; it is not possible to explain this inconsistency. c. planet earth is abundant in water, but there is no way to scientifically determine from where earth's water originated. d. earth is shaped like a sphere even if not all of the scientific observations related to its shape support this idea.