The soft annd spongy layer of skin over the visceral hump of molluscs is known as:

The soft and spongy layer of skin over the visceral hump of molluscs is known as:

A soft and spongy layer of skin forms of mantle

Visceral hump in mollusc is covered by

Visceral hump in mollusc is covered by

In 1980s atmospheric scientists working in Antarctica reported about depletion of ozone layer commonly known as ozone hole over the South pole. Which of the statements are correct ?