I have the questions attached below. The assignment is about evolution. I already completed the first two parts and have the third part left. Here's the background:
"Stickleback fish protect themselves from predators with a thick covering of brownish plates. They feed on small aquatic organisms and are preyed upon by bigger fish like trout. In a certain lake, the number of stickleback fish was documented over a period of 30 years. During this time, the clarity of the lake water also changed.

This worksheet was developed to support use of The Virtual Stickleback Evolution Lab in the classroom. The lab emphasizes quantitative measurement of phenotypic diversity in related stickleback populations and encourages inquiry into the role of natural selection and underlying genetic mechanisms. Before doing the virtual lab, students would benefit from watching the HHMI short film The Making of the Fittest: Evolving Switches, Evolving Bodies, available at  The worksheet is meant to provide students with structure and guidance as they perform the tutorials, experiments, and quizzes in the lab. There are two versions of the worksheet: an advanced version and a basic version. The only difference between them is that the basic worksheet does not contain the chi-square analyses portions of the lab. Each worksheet can be further modified by crossing out certain sections that students will not be performing. (For example, some students may not carry out one of the experiments in the lab.)

Explanation:

substitution is the answer in this case