How many half lives will have passed if 7500 atoms of carbon-14 remain? How old would the rock be? ANSWER QUICK PLSS (the topic is actually integrated science but they didn't have that option :/)

During a fierce storm a large number of tall trees on an island are uprooted by the wind and die. most of the trees on the island are now short trees and produce seeds that grow into short trees. what concept is shown in this example? question 5 options: natural selection artificial selection genetic engineering gene splicing