Question

16. When shellfish have cooked, their edges A. crisp B. curl. C. burn. D. soften.

Answer 1

Raw shrimp: it will turn pink and become firm
Live oysters, clams, and mussels: the shells will open when they are done
Shucked oysters, clams, and mussels: they will become plump and opaque. The edges of the oysters will start to curl
Scallops: they will turn white or opaque and become firm to the touch
Crab and lobster: the shells will turn bright red and the meat will become white or opaque.

Answer 2

Answer:

When shell fish have cooked their edges curl.

Explanation:  As per the Professional Chef page 535