Photosynthesis generally occurs in which portions of the plant?

Answer: (a) Leaf and other chloroplast bearing parts

Photosynthesis happens in chloroplasts — mainly leaves, but also green stems, sepals and unripe fruits.

The idea

Photosynthesis happens inside chloroplasts, the small green bodies that hold chlorophyll. So the rule is not “in leaves” but “wherever there are chloroplasts”. Any green part can do it.

Leaves: the main site → Green stems: cactus, young shoots → Unripe green fruits and sepals → Roots, bark, woody stems: no chloroplasts → no photosynthesis

Why the others are wrong

(b) Most stems (woody ones) do not photosynthesise — only green stems do.

(c) Roots grow in the dark and have no chloroplasts.

(d) Bark is dead cork tissue.

The trap

(b) sounds safe because leaves are included. The key word is “chloroplast-bearing”.

Also know

In a cactus the leaves have become spines and the thick green stem does all the photosynthesis. A few plants even have green photosynthetic roots, such as some orchids that hang in the air.