Answer:
The correct answer is - Swimmerets.
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.
Pepsin functions best in acidic environments and is often found in an acidic environment, particularly those with a pH of 1.5 to 2".
"Trypsins have an optimal operating pH of about 8".
It seems that the highest level of activity for the two if they were in the same environment would have to be midway between their optimum range - about pH 5
