"Runner's High" occurs when prolonged, intense athletic activity causes the release of _______, in the brain's natural painkiller.

Four-year-old Rebecca shouts loudly that her teacher forgot to let her have a turn to share a toy with the class. Rebecca always makes sure her needs are met and she speaks loudly if necessary. Also, Rebecca loves to be first in line

In games, she feels the need to win and when she doesn't win, she sulks. Rebecca's behavior is an example of a(n) ___________ orientation. a. individualistic c. economic b. spatial d. collectivistic

The __________ will form muscles, bones, and the circulatory system

a. ectoderm c. placenta b. mesoderm d. endoderm