NSES Content Standard C  Life Science: Structure and function in living systems  Grades 5-8, page 157  Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms.

 
Benchmark 6E The Human Organism: Physical Health
Grades 6-8, page 145
Viruses, bacteria, fungi, and parasites may infect the human body and interfere with normal body functions. A person can catch a cold many times because there are many varieties of cold viruses that cause similar symptoms.

Benchmark 6E The Human Organism: Physical Health
Grades 9-12, page 146
Some allergic reactions are caused by the body's immune responses to usually harmless environmental substances. Sometimes the immune system may attack some of the body's own cells.

Benchmark 6E The Human Organism: Physical Health
Grades 9-12, page 146
Faulty genes can cause body parts or systems to work poorly. Some genetic diseases appear only when an individual has inherited a certain faulty gene from both parents.