The length and quality of human life are influenced by genes and environmental factors, including sanitation, diet, medical care, and personal health behaviors.
For Grades: 9-12
Learning Goal 3
Communication between cells is required to coordinate their diverse activities. Cells may secrete molecules that spread locally to nearby cells or that are carried in the bloodstream to cells throughout the body. Nerve cells transmit electrochemical signals that carry information much more rapidly than is possible by diffusion or blood flow.
For Grades: 6-8
Learning Goal 2
Toxic substances, some dietary habits, and some personal behavior may be bad for one's health. Some effects show up right away, others years later. Avoiding toxic substances, such as tobacco, and changing dietary habits increase the chance of living longer.