Please help!! What social or cultural aspect of the U. S. impact the expectation that a parent return to immediate productivity after childbirth?

Animals will lose energy because it is converted to heat

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.