The following steps are involved in muscle contraction: (1) The sequence of events leading to contraction is initiated somewhere in the central nervous system, either as voluntary activity from the brain or as reflex activity from the spinal cord.
The average Mexican man weighs 165 pounds and stands 5 feet 4 1/2 inches tall, while the median figures for Mexican women are 151 pounds and 5 feet 2 inches, according to a study released by a group representing Mexico's clothing industry.
Mexicoâs population and its land area of756,000 square miles (1.9 million sq. km) give it apopulation density of 132 people per square mile (51people per sq. km), making Mexico seem relativelyuncrowded.