An estimate of heritability applies only to a particular group living in a particular environment

By the age of 10, which of the following sentences regarding friendships is true?

Girls are more interested than boys in maintaining long-term friendships. Boys prefer to be popular among peer groups; girls want to have best friends. Both boys and girls want to have best friends. Mutual loyalty is more important to boys than it is to girls.

To help her students understand the various parts of a neuron, an instructor compares a neuron to an electrical cord. Using this analogy, how would the instructor describe the myelin sheath?

a) the insulating cover b) the internal copper wire c) the receptacle end of the cord d) the plug that goes in a wall socket