Which of the following best explains the concept of radioactive dating?

radioactive elements decay at a rate that is directly proportional to temperature, and scientists can compare the amount of a radioisotope at different temperatures to determine a sample’s age.
radioactive elements break down at an unpredictable rate, and scientists measure the amount of a radioisotope and compare it to the concentration of other radioisotopes to determine a sample’s age.
radioactive elements break down at a predictable rate, and scientists compare the amount of a radioisotope to its decay products to determine the sample’s age.
radioactive elements decay at a rate that is inversely proportion to pressure, and scientists can measure the amount of radioisotope in different rock layers to determine a sample’s age.

Which would be the most useful source of evidence to support mcneill's contention?

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).

Pls need ! in your opinion, what are the limiting factors that might affect the growth or diversity of our ecosystem? respond to this question in claim, evidence, reasoning format. 1. make your claim (i are the limiting factors that might affect the growth or diversity of our 2. follow the claim with 3 pieces of evidence. evidence may be taken from the reading, the videos, previous lessons, or googled answers. site sources, too. 3. use reasoning to explain why you chose your evidence.