Answer:
C) II and III only
Explanation:
Option 1 is not an example of phenotypic plasticity because each person is born with their own blood type and this doesn't change based on their environment and behavior.
Option 2 is an example of phenotypic plasticity because a person's red blood cell counts can increase based on their environment, i.e. moving to Denver, CO from Death Valley, CA. The higher elevation and decreased oxygen causes your body to produce more red blood cells.
Option 3 is an example of phenotypic plasticity because one twin can be taller than another because of differing behaviors, environments, etc.
