The jimson weed plant, datura wrightii, grows in arid regions of the southwestern u. s. and mexico. there are two phenotypes of this plant, one with sticky trichomes (hair-like structures) on its leaves and one with velvety smooth leaves. in an effort to understand if there is an advantage to having sticky leaves—if the sticky leaf plants were better protected from herbivores—scientists grew both types of the plant in a greenhouse from seed. after three weeks, they transplanted the plants to an outdoor experimental garden and sprayed some of each type of plant (sticky and velvety) with insecticide to deter herbivores and left ot

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).