There isn't a responsible muscle because your back muscles calf and thigh muscles work together also to help get momentum you swing your arms up.<span />
Hypothesis: I believe an increase in temperature would lead to a decrease in surface tension.
Here's why: As the temperature increases, the molecular interaction between the liquids molecules becomes weaker because the hydrogen bond is the main factor for association between two molecules. It is a very weak bond to begin with, so when the temperature increases, it just further weakens it.
If the allele frequency of a gene for brown fur is increasing from 15 to 25 percent, the population of the bears is evolving.
We could possibly use water as a fuel source, rather than fossil fuels (which are limited)
Science has already developed something of the sort, and with using water as a fuel source for say vehicles and such, it's inevitable for a positive change to happen because there would be less carbon monoxide; which means less polution.
