Ans:- When the silkworm ate great quantity of Mulberry leaves, they were digested and nutrients were sent into the bloodstream. The silk glands absorbed these nutrients. The larva has a small spinneret on it lips, through which the silk emerges. The silkworm moves its head as it spins the cocoon.

Silkworms, which are the larval stage of the silk moth, have the unique ability to spin silk, which they use to create their cocoons. The process of silkworms spinning their cocoon is a crucial step in sericulture, which involves the cultivation of silk.

The following are the steps involved in how silkworms spin their cocoon:

1. Preparing for the cocoon spinning process
Before silkworms begin spinning their cocoon, they go through a process called "pre-pupa" where they stop eating and start to move around in search of a suitable spot to spin their cocoon. During this stage, they also secrete a special silk protein from their salivary glands, which they will use to create their cocoon.

2. Spinning the cocoon
Once silkworms have found a suitable spot, they start spinning their cocoon. They first form a silk pad to attach themselves to the surface they will be spinning on. They then create a single strand of silk and begin to wrap it around themselves in a figure-eight pattern, forming the basic structure of the cocoon. Silkworms continue to spin and wrap the silk around themselves, creating a layered structure that is strong and protective.

3. Completing the cocoon
After several days, silkworms complete spinning their cocoon. The cocoon is made up of a single strand of silk that can be over 900 meters long, which is wrapped around the silkworm's body in multiple layers. The cocoon is a protective shell that keeps the silkworm safe while it undergoes metamorphosis into a silk moth.

In conclusion, the process of silkworms spinning their cocoon involves the secretion of silk protein, the creation of a silk pad, and the wrapping of a single strand of silk around their body in a figure-eight pattern. The resulting cocoon is a strong and protective structure that keeps the silkworm safe during metamorphosis. This is an important step in sericulture, which involves the cultivation of silk.