18. How has the use of herbicides affected agricultural productivity? O A. Fewer crops are organic because of the use of Bt toxin.
B. Fewer pesticides are needed because of parasitoids.
O C. Fewer people are needed to weed because of herbicides.
D. Fewer crops are produced because of herbicides.

The probability of producing a normal child by two parents who are carriers for an autosomal recessive disorder is

Which of the following is the most likely outcome of global warming

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).