What treatment do we have for bacterial infections?.

antibiotic

Explanation:

or something like that

Many human illnesses are caused by infection with either bacteria or viruses. Most bacterial diseases can be treated with antibiotics, although antibiotic-resistant strains are starting to emerge. Viruses pose a challenge to the body's immune system because they hide inside cells.

Includes Diseases: Hepatitis A

A general term for narrowing would be contracting. I assume that this is applicable to the rectum, as it is a muscular tissue, and muscles are able to expand (extend, rather), and contract.

Hope this helps. And I hope I'm the brainliest!