Why did the researchers present unshelled northern and southern periwinkles to northern and southern crabs in the second experiment?
a) to test if crabs preferentially selected prey based on the color of their shells
b) to feed crabs that were unable
c) to open the periwinkles provided as potential prey
d) to test if either population of periwinkles was unpalatable to either population of crabs

The researchers present unshelled northern and southern periwinkles to northern and southern crabs in the second experiment to test if either population of periwinkles was unpalatable to either population of crabs.

Option D

Explanation:

The researchers picked up crabs and periwinkles from the northern and the southern location of Gulf of Maine. Then an individual crab was inserted into hutch companied with 8 size variable periwinkles. Following four set-ups were organized, where crabs involved were of both gender but not size variable and these set-ups were analyzed 12-14 times:

After three days of experiment conclusion drawn was: southern crab killed more number of northern periwinkles when compared with rest three set-ups. While second is northern crab and northern periwinkles, third is southern crab and periwinkles and fourth is northern crab and southern periwinkles.

Now, same set-ups as above was organized but with unshelled northern and southern periwinkles and conclusion researchers found that crabs catered themselves with all unshelled periwinkles within 1 hour to test if either periwinkles population was unpalatable to either crabs population.

a: social security and social programs