Smog. Im pretty sure smog is the only unhealthful air pollution on this list.
Organisms that absorbs and uses nutrients of living or dead organisms are called saprophytes.
Answer:
In autoimmune diseases, such as lupus, multiple sclerosis and rheumatoid arthritis, people produce antibodies that stick to their body's own proteins and attack healthy cells.
Explanation:
Binary fission enables them to reproduce quickly.