Question

Egg cases of sharks, skates, and rays (chondrichthyes) are primarily composed of:

a) Calcium carbonate
b) Keratin
c) Chitin
d) Collagen

Answer 1

The egg cases of sharks, skates, and rays (chondrichthyes) are primarily composed of keratin.

Step-by-step explanation:

The egg cases of sharks, skates, and rays (chondrichthyes) are primarily composed of keratin. Keratin is a protein that provides structure and durability to various parts of organisms, including the outer layer of skin, hair, and nails. Sharks, skates, and rays have a tough, leathery egg case called a mermaid's purse that protects the developing embryo.