Answer the following question given this paragraph: 

Figure 5.7 Not all cells of a leaf carry out photosynthesis. Cells within the middle layer of a leaf have chloroplasts, which contain the photosynthetic apparatus. (credit "leaf": modification of work by Cory Zanker).


Q: Not all cells of a leaf carry out photosynthesis. cells within the middle layer of a leaf have chloroplasts, which contain the photosynthetic what?

 Choices:

- pipes

- structure

- wires

- apparatus

A:
apparatus
