The leaf originally contained 12 grams of 14C. The fossil of the leaf you found contains 3 grams of 140. If your fossilized leaf underwent one more half-life, how many grams of 14C would it contain?

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

Which of the following describes a negative feedback loop? when the heart rate is too high, the body sends hormones that continually increase the heart rate higher. when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones. when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows. when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.

Up until 1938, paleontologists accepted the idea that coelacanths (an ancient fish) went extinct at the time that they last appear in the fossil record, about 80 million years ago. but in 1938, a live coelacanth was discovered off the coast of south africa that was compared to the fossil record and found to be the same species what goal of science does this discovery represent