Which of the following best describes a controlled experiment? a. An experiment repeated many times to ensure that the results are accurate b. An experiment includes at least two groups, one of which does not receive the experimental treatment c. An experiment that includes one group for which the scientist controls all variables d. An experiment that includes at least two groups, one differing from the other by two or more variables

Beth’s hygrometer is reading a temperature of 30 c and a relative humidity of 65%. the humidity in the air is?

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).

What part of the body contains bile, an enzyme that break down lipids?