Answer:
Darwin noted that not all offspring that are born survive, that there is variation in the population, and that there is a struggle for survival.
Explanation:
The theory of evolution, proposed by Darwin, is based on some key points: common ancestry and natural selection, which proposes that the most suitable organisms survive. In any group of species, all individuals have common ancestors at some point in evolutionary history. Thus, they are descendants of them with modifications and result from natural selection.