The swollen underground structure in an onion is known as .........

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.

One of the single internodal branches is found in:

What is most affected in a hollow stem?

An underground specialised shoot with a reduced disc-like stem covered by fleshy leaves is:

Stem modified into green,flattened branches of unlimited growth for assimilatory function is