Question

7 multiple choice 2 points what happens to the energy in an ecosystem when organisms die and decomposers break them down? it is lost from the ecosystem. it is converted into matter. it is stored as potential energy. it is recycled as nutrients. 8 multiple choice 2 points what are biogeochemical cycles? the study of rocks and minerals the pathways that elements and compounds follow through earths systems the movement of organisms within ecosystems the study of ancient life forms 9 multiple choice 2 points what is the primary role of the nitrogen cycle in ecosystems? to maintain the balance of atmospheric gases to regulate the carbon cycle to provide energy for photosynthesis to supply nitrogen, an essential nutrient, to living organisms

Explanation:

• Question 7: Decomposers break down dead organisms. Energy is lost as heat (following the second law of thermodynamics) and is not recycled in the same form. Nutrients (matter) are recycled, but the question is about energy.
• Question 8: Biogeochemical cycles are defined as the pathways that elements and compounds (like carbon, nitrogen, water) follow through Earth's systems (biosphere, geosphere, hydrosphere, atmosphere).
• Question 9: The nitrogen cycle's main role is to convert atmospheric nitrogen (\(N_2\)) into forms (like ammonia \(NH_3\), nitrate \(NO_3^-\)) that can be used by living organisms (as nitrogen is an essential nutrient for proteins, nucleic acids etc.).

Answer:

• 7. It is lost from the ecosystem.
• 8. The pathways that elements and compounds follow through Earth's systems.
• 9. To supply nitrogen, an essential nutrient, to living organisms.