Outlines the system to be used for identifying and remedying land contaminated by radioactive substances.

These are suspected to be a result of the high purity, or adulteration by unknown substances, of the drugs involved.

The body has a defence mechanism to protect it from invasion by foreign substances.

It forms upon illumination or natural catalytic action by substances containing in water.

The immune system defends the body against infection and invasion by foreign substances in two ways.

The nasal mucosa membrane protects the inside of your nose against invasion by foreign substances.

It works by decreasing substances in the body that narrow blood vessels and raise blood pressure.

They protect the body from damage by substances called free radicals.

They do that by trapping cancer cells, bacteria, and other harmful substances.

The body reacts to the entry of any foreign materials (antigens) by developing substances called immune bodies.