An environmental change puts pressure on a population. Which of the following is the best description of how an adaptation might occur?

i believe the answer is a or 1

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements