Selective breeding programs, such as those that produce throughbreds, and captive breeding programs, such as those used to increase the takhi population, have different outcomes. Which statement both describes an outcome of one type of breeding program and is supported by the information about the takhi? Select one:
A. Long-term slective breeding for specialized traits produces high-quality genes that improve a species’s changes of continued survival.
B. The takhi captive breeding program has proven that only a few individuals are necessary to produce a population with traits that ensure survival.
C. Long-term selective breeding for specialized traits can make it less likely that individuals will express desired traits.
D. The takhi captive breeding program has demonstrated that populations with genetic diversity have a greater likelihood that some individuals will have traits that favor survival.

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).