Concept:Natural selection is the process by which organisms best suited to their environment survive and reproduce, while less suited ones are eliminated.
Explanation:Charles Darwin proposed that living things produce more offspring than the environment can support.
This creates a struggle for existence among individuals.
Some individuals possess favorable traits that help them survive and reproduce.
Individuals with weak or unfavorable traits are more likely to die before reproducing.
Over time, the weak traits are removed from the population, and the strong traits become common.
Option A is wrong because struggle for existence is a key part of natural selection.
Option B describes long-term adaptation, but it does not directly explain how natural selection works.
Option D refers to vestigial organs, which is not the main idea of natural selection.
Therefore, the statement that weaker offspring are eliminated best explains the theory of natural selection.
Answer:C. The weaker offspring are eliminated.