The force that attracts all matter to each other is gravity, i believe.
A mutation may result change in the way you look, you could lose sight, could be born with some genetic issues.
Human muscle cells also use fermentation. This occurs when muscle cells cannot get oxygen fast enough to meet their energy needs through aerobic respiration. There are two types of fermentation: lactic acid fermentation and alcoholic fermentation. Both types of fermentation are described below.