Tall pea plants are dominant over short pea plants. can a short pea plant ever be produced from crossing two tall pea plants?
a. no, only short pea plants can produce short pea plants because it is a recessive trait
b. no, short pea plants are a different type of pea plant and could never be the offspring of tall pea plants.
c. yes, two heterozygous tall plants could produce short pea plants.
d. yes, two homozygous tall pea plants could produce short pea plants.

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).