Marine animals are harmed by toxic chemicals and by frequent shipwrecks lack of eutrophication sewage treatment runoff discarded plastic nets and fishing lines

Answer

D. Discarded plastics nets and fishing lines

Explanation

Plastic nets and fishing lines discarded into water bodies are examples of solid waste pollution on water bodies. These items potentially lower the quality of water thus putting the life of marine animals at risk. Other  factors that can harm marine life are oil spillage, runoffs containing farm fertilizers which cause eutrophication, and  untreated sewage released to water bodies.

the answer to the question is punishment. or more specifically, positive punishment.

positive punishment occurs when a behavior is given a negative consequence for the individual doing the behavior.

sara no longer wants to ask questions (the behavior) because she is ridiculed by mr. smith (the punishment).

reinforcement is inaccurate because reinforcement always gives positive consequences for the individual doing the behavior, be it by introducing a pleasant consequence or removing an unpleasant one.