R
radiation [ray dee a shun]
Any energy that is produced in the form of rays or waves such as: light, heat, or sound.
rappel [ra pel]
To go down a steep slope or cliff by using a rope that is tied at the top and is passed though a special harness worn by the climber.
rectum
The last segment of large intestine right before the anus
riboflavin [rye bow flay ven]
Also call Vitamin B2. Helps maintain a healthy nervous system, eyes, and skin. Riboflavin is required for the release of energy from carbohydrates and the development of red blood cells.
risk factor
anything that increases the possibilty of getting a disease like cancer
rookery [rook er ee]
A living or breeding area used by large colonies of birds or sea mammals.
run-off
Water from rain or melting snow or ice that does not soak into the ground, but runs into downhill into streams and rivers.