The carbon cycle includes processes that release carbon into the atmosphere and places that act as carbon reservoirs. The diagram below shows both major processes that release carbon and major carbon reservoirs. Which of these disruptions would cause an excess output in the carbon cycle?

The diagram below represents the nitrogen cycle in a student's aquarium. Ammonia, nitrites, and, to a lesser degree, nitrates can be harmful to fish. The student wants to keep the nitrogen in this aquarium cycling normally without having to continually change the water. Which of the following should the student add more of to help remove nitrates and improve the natural cycling of nitrogen in this aquarium?

The diagram shows the flow of organic molecules through an ecosystem. One process that occurs in this ecosystem is labeled X, and another process that occurs is labeled Y. Which two processes are identified by the labels X and Y?

This diagram demonstrates why the ocean is a large carbon sink. An increase in the amount of carbon dioxide in the atmosphere can cause atmospheric temperatures to increase. Which statement explains how this could affect the ocean as a carbon sink?