Q: What is a fold of the outer skin lining the shell called?


Read this paragraph and choose the correct option from the provided answers:

A mantle , or fold of the outer skin lining the shell. The mantle often releases calcium carbonate, which creates an external shell, just like the ones you find on the beach. The shell is made of chitin , a tough, semitransparent substance.

 Choices:

- marble

- cortex

- stack

- mantle


A:
mantle