To see if they remember what they had that morning (to determine whether they have long term or short term memory loss)
Answer:
a. insulation
Explanation:
The myelin sheath provides increased cell isolation (increased membrane resistance) because there are no membrane leakage channels in which there is myelin.
In addition to no membrane leakage channels, there is also virtually no type of membrane channel when there is myelin sheath (eg sodium and potassium pumps), which causes the cell a lower need for protein synthesis, or that is, less energy expenditure.
The pollution from the Industrial Revolution darkening the trees. After the trees darkened from all the soot in the air, the white moths were easier to see and more vulnerable to predators. The dark moths blended into the dark tree bark.