Answer:
The correct answer is - Swimmerets.
Step-by-step explanation:
Swimmerets are small paddle-like appendages that are modified pairs of legs near the rare. or attached to the abdomen. These paddle-like appendages are help crabs to swim and also helps in carrying and aerating eggs.
These are present in lobster, and shrimps as well as swimming crabs. These are the modification of the legs of the crabs in order to better swimming and brooding of the eggs.