What type of evolutionary adaptations did plants acquire to allow them to grow in areas that were not directly on a water source? A. Angiosperms evolved flowers, which could catch rainwater, reducing the dependence on ground water sources. B. Vascular seedless plants evolved specific structures to transport and hold fluids, reducing dependence on water sources. C. Gymnosperms evolved seeds, which they could alter to need less water. D. Non vascular plants evolved chloroplasts to allow them to get energy from the sun, instead of relying on water for energy.

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).