Question

in a grassland ecosystem, plants use sunlight, water, and carbon dioxide to produce food through photosynthesis, and herbivores rely on plants for energy. which elements of life are directly involved in the flow of energy and matter in this ecosystem?
nitrogen, sulfur, and phosphorous
carbon, nitrogen, and oxygen
oxygen, nitrogen, and sulfur
carbon, hydrogen, and oxygen

Explanation:

Step1: Analyze photosynthesis reactants and products

Plants use \(CO_2\) (carbon - containing), \(H_2O\) (hydrogen - and oxygen - containing) for photosynthesis. The products are glucose (\(C_6H_{12}O_6\)) and \(O_2\).

Step2: Consider herbivore energy source

Herbivores eat plants. Plants' main components (from photosynthesis products) involve carbon (from \(CO_2\)), hydrogen (from \(H_2O\)), and oxygen (from \(H_2O\) and \(CO_2\)). Nitrogen, sulfur, and phosphorus are not directly part of the basic photosynthesis - based energy and matter flow described (e.g., not in the simple glucose - based plant energy storage and transfer to herbivores as per the given description).

Answer:

Carbon, hydrogen, and oxygen.