Answer the following question given this paragraph: 

Ecosystems need energy. Many ecosystems get their energy in the form of sunlight, which enters the ecosystem through photosynthesis . This energy then flows through the ecosystem, passed from producers to consumers . Plants are producers in many ecosystems. Energy flows from plants to the herbivores that eat the plants, and then to carnivores that eat the herbivores. The flow of energy depicts interactions of organisms within an ecosystem.


Q: Energy from sunlight enters many ecosystems through what process?

 Choices:

- multiplication

- reproduction

- isolation

- photosynthesis

A:
photosynthesis
