The cerebrum is the major part of the brain and is responsible for the main senses (thinking, hearing, seeing).

The columns of the Periodic Table are called groups and all elements in a group have the same number of electrons in their outer electron shell. The group that an element occupies generally determines its chemical properties as the number of outer shell electrons establishes the way it reacts with other elements to form molecules. So, because each element has the same number of electrons in its outer shell, each has similar reactivity.

Heredity is the passing on of physical or mental characteristics genetically from one generation to another. Heredity is made possible via large strings of chromosomes which carry information encoded in genes.

If the ovum fails to become fertilized, the lining of the uterus sloughs off during menstruation. From puberty to menopause, this cycle of menstruation repeats monthly (except during pregnancy).

Tough fibrous cords of connective tissue called tendons connect muscles to the skeleton while another type of connective tissue called ligaments connect bones to other bones at joints (elbow, knee, fingers, spinal column).