15 POINTS ANSWER FAST -- Choose the correct description of a comet. a large meteor that appears as a fireball once it strikes the atmosphere with a tail
bodies of ice and rock that orbit the Sun and produce a coma and tail of vapor and dust when near the Sun
rocky bodies that ranging in size from a meter to 900 km orbiting between Mars and Jupiter
concentrations of meteors called showers that the Earth passes through in its orbit annually

Robert wants to know which fertilizer will work the best for his grass. what can he do to explore this inquiry?

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).

Consider the following planned experiment. factor experimental group control group light exposure tots of sun tots of sun amount of water weekly weekly type of soil nutrient rich nutrient rich size of pot large which variable is being tested in this experiment? small a. size of pot b. type of soil c. light exposure d. amount of water