Which has more energy for  erosion? rainfall lake slow-moving creek fast-moving stream

The diagram illustrates the activity of vesicles during a cellular process.

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000