The correct answer is leaves. Leaves are the most photosynthetic cells in plants found. That is mainly because the sunlight goes through the leaves. The photosynthesis simply takes place first in leaves. They are the one responsible for the entrance of the carbon dioxide and the release of the oxygen.
Leaves are definitely where most of the photosynthetic cells are in plants. Since leaves are mostly flat and broad, they provide an ample surface for absorbing light.
