Question

An example of an edible underground stem is
A. Carrot
B. Groundnut
C. Sweet potato
D. Potato

Answer 1

Hint: Stem belongs to the shoot system in plants. They are often erect and have nodes that give rise to leaves. There are few modifications that occur in stems that give rise to the underground stem.

Complete answer:
The morphology of plants contains the root system i.e. underground part of the plant and the shoot system i.e., part of the plant that is above the axis i.e. above the ground. The root system comprises primary roots and secondary roots while the shoot system in plants comprises Flowers, fruits, stems, leaves, nodes (part from which leaves arises), and internode (the part between the nodes). The root, stem, and leaves constitute the vegetative parts of the body whereas the fruits, flowers, and seeds constitute the reproductive system of the body. These plants undergo few modifications so that the plant can survive in adverse conditions like floods, drought, etc. There are few modifications in the stem that gives rise to the underground stem. These modifications are:
-A rhizome is a modified stem that has nodes and internodes and can give rise to a vertical shoot, ex. ginger.
-A corm is similar to a rhizome but is more fleshy and round. It contains stored food that helps plants to survive in winter. E.g. Gladiolus.
-Stolon is a stem that runs parallel to the ground below, that can give rise to a new plant, ex. silverweed.
-A bulb is a modified stem that functions as an underground storage unit and are large and fleshing leaves emerging out of it. e.g. spring onion.
-The tubers are modified stems that store starch. e.g. potato.
Hence, the correct option will be option D- Potato.

Note: Just like these modifications of stems that are underground, there are runners that are modified stems but run above the ground or just below the surface that can give rise to new clone plants at different intervals. e.g. strawberries.