Photosynthesis in $Opuntia$ is performed by:

Although potato tuber is an underground part,it is considered as a stem. Give two reasons.

Colocasia is a

In $Chrysanthemum$,the stem is modified to $.......$.

In $Opuntia$,the stem is modified into a flattened green structure to perform the function of leaves (i.e.,photosynthesis). Cite some other examples of modifications of plant parts for the purpose of photosynthesis.

Describe the modifications of the stem for food storage.