Soft-shell crab is a prized dish in many seaside resorts. Why are the crabs' shells soft?
A) The crab has just moulted and the new exoskeleton has not yet hardened.
B) These species of crabs live under rocks and therefore have lost the hard exoskeleton over evolutionary time.
C) These species have evolved a light and soft exoskeleton so that gases can diffuse directly between body of the crab and the surrounding water.
D) These species have evolved a light and soft exoskeleton so that they can float in the water column.

Question

Quizplus · Accepted Answer

Soft-shell crabs have just moulted and shed their hard exoskeleton. During this period, they are vulnerable to predators but their soft shell makes them a delicacy for humans.

Soft-Shell Crab Is a Prized Dish in Many Seaside Resorts