A cell membrane is compared to a window screen because of its translucent properties. Like it allows oxygen to come through or it resists invader who tries to come into the cell.
Your answer is Cell membrane.
The answer for Part A is: In an action-reaction pair the forces work on different objects.
The scientist can conclude that the plants that were used in this experiment contained both a dominant and recessive allele. That the plants were hybrids which causes the off springs to have a 3:1 ratio.
