Choices: (1). insects. (2). root growth. (3). Plants growth. (4). Animal survival. (5). animals. (6). Plant reproduction. (7). mammals. (8). specialization.

Fact 1: Specialization occurs when competing species evolve different adaptations. Fact 2: Adaptation is the result of natural selection. Given the two facts above, natural selection results in:?
Answer:
(8).