I think the correct answer is B.
How can regular participation in physical activity improve an
individual's overall health?
a. regular participation in physical
activity reduces the risk
of developing various diseases.
A hazardous material is any item or agent ( it can be biological, chemical, radioactive, and any sort of physical object ), that has the potential of harming any biological creature or the environment (by biological we mean humans, animals etc.)
Any substance that is a health hazard is a hazardous material. Here are some examples : chemicals with carcinogents, toxic agents, sensitizers etc.
This system helps the respiratory system by protecting the lungs. The circulatory system is very useful. This system transports the food nutrients, and oxygen to the body cells. It also delivers of carbon dioxide and waste products.
