The Eustachian tube is used to equalize air pressure between the middle ear and the surrounding area, but it is also used to drain mucus from the middle ear. Keeping the pressure in a person's head equalized helps with balance and preventing dizziness.
Mutations can also be caused by environmental foes. Tobacco, ultraviolet light and other chemicals are all potential enemies of DNA. One way these hazards attack our genes is very sneaky: They have the ability to damage the chemicals making up DNA.
1 This results in changes in the proteins that are made. 2  This can be a bad or a good thing. 3  Mutations can occur during DNA replication if errors are made and not corrected in time. 4  Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation.