Answer the following question given this paragraph: 

Leaves are the keys not only to plant life but to all terrestrial life. The primary role of leaves is to collect sunlight and make food by photosynthesis. Despite the fundamental importance of the work they do, there is great diversity in the leaves of plants. However, given the diversity of habitats in which plants live, it’s not surprising that there is no single best way to collect solar energy for photosynthesis.


Q: What is the part of a plant whose primary role is to collect sunlight and make food by photosynthesis?


A:
leaves