Carbon contributes an electron, and Hydrogen contributes an electron. The sharing of a single electron pair is termed a single bond. When two pairs of electrons are shared, a double bond results, as in carbon dioxide.
Elements of nervous system involved in motor coordinationEdit. The red nucleus is mainly involved in motor coordination of the muscles of the shoulder and upper arm, but it has some control over the lower arm and hand as well.
The combination of a motor nerve and the group of muscle fibers that it innervates is called the motor unit. Each branch of a motor nerve in a motor unit extends to a separate muscle fiber. All the muscle fibers that constitute such a unit contract almost simultaneously when they are excited.