What is happening during the plateau phase of
cardiacdepolarization?
a) sodium ions block voltage-gated calcium ion channels.
b) acetylcholine is hyperpolarizing the sa node
c) nothing - all ion gates and valves are closed.
d) voltage-gated potassium ion channels open to allowpotassium
ions to diffuse out.
e) calcium ions enter the cystol of cardiac myofibers
fromsarcoplasmic reticulum and through voltage-gated
slowchannels.

Which best compares habitat and niche? o niche is a place in which organisms live, and habitat is the way in which an organism fits into its habitat. o habitat is a place in which organisms live, and niche is the way in which an organism fits into its habitat. habitat is a group of organisms that live in an area, and niche is a specific species that lives in that areao niche is a group of organisms that live in an area, and habitat is a specific species that lives in that area.

According to the cladogram, which organisms have roundworms as a common ancestor?

The kidney filters potentially toxic substances in the blood, and thus “clears” the blood of those substances. this clearance function is dependent upon and proportional to the diffusion gradient of the substance across filtering capillaries, i. e. if the concentration of the substance is doubled, twice as much will be cleared from each ml of blood that is filtered. suppose that the body produces a constant amount of a substance x per unit of time. the kidneys eliminate substance x at a rate directly proportional to the concentration of the substance and the volume of blood cleared each minute (c): elimination = c × [x], where [x] is the steady-state concentration of substance x. imagine an individual with an initial concentration of x equal to [x]0 who develops kidney disease. her baseline clearance c0 drops to one half of the original (½c0). what is the new steady state concentration of x? (for simplicity, assume that substance x is 100% filtered by the kidney).