Tubers - they can act as both a source and sink for molecules such as glucose
The best answer to the question 'What are the nonliving components of the environment that shape an ecosystem?' would be letter d. Abiotic factors are those components of the environment that are non-living or does not have life. All the other choices have life.
No I think you need to do some more research
Chemical changes are not usually physical so you can’t see them I guess so I would put D
