Callus culture is useful for purposes like

The correct option is D All of the above

Callus culture is useful for many purposes:

1 Callus is the starting material for the suspension culture which cells are separated.

2. It helps in the production of secondary plant products.

3. It is useful for the synthesis of starting compounds that are subsequently modified to yield the desired product.

4. It is the starting materials for vegetative propagation of plants.