Solution:

Modifications of stem:

Food storage:

Potato, ginger, and turmeric underground stems have been adapted to store food. They function as perennation organs, allowing them to survive in environments that are not conducive to growth.

Tendrils: Tendrils are spirally coiled thin stems that emerge from axillary buds. Plants such as gourds (cucumber, pumpkins, and watermelon) and grapevines use these stem tendrils to help them climb.

Thorns:

Auxiliary buds’ stems are transformed into woody, straight, and pointed thorns. Plants are protected by thorns against animals. Several dry-land plants change their stems into fleshy cylindrical structures or flattened structures. Ex: citrus plants. They possess chlorophyll and perform photosynthesis.

Other modifications:

Vegetative reproduction:

Some plants, such as grass and strawberry, stretch underground stems to new niches, and when older sections die, new plants emerge. A slender lateral branch emerges from the base of the main axis in plants like mint and jasmine, and after growing aerially for a while, arch downwards to touch the ground.