What trophic level contains organisms that are the source of all chemical energy used in an ecosystem?

Which could be a pathway of food through an ecosystem

What vitamin gives carrots and sweet potatoes their orange color?

How do energy and matter move through an ecosystem? both energy and matter unidirectionally flow through an ecosystem. both energy and matter cycle within an ecosystem. matter unidirectionally flows through an ecosystem, whereas energy cycles within an ecosystem. energy unidirectionally flows through an ecosystem, whereas matter generally cycles within an ecosystem.