According to the theory of evolution by natural selection, the following statement is true:
The environment will determine the favorable traits that will be passed on to the offspring.
Natural selection occurs when individuals with traits that are advantageous in their environment have a higher likelihood of surviving and reproducing, thereby passing those traits on to the next generation. The other statements you provided are incorrect in the context of evolutionary theory:
- Traits that lead to evolution are not acquired during the lifetime of the organism and passed on; this is a misconception known as Lamarckism. Evolutionary changes are based on genetic variation that exists in a population.
- While some animals can adjust to changing environments, not all can do so easily, and the ability to adapt varies widely among species and contexts.
- Variation exists between members of the same species; it is this genetic variation that is essential for natural selection to act upon.