What are the various routes by which transmission of human immunodeficiency virus takes place?

Explanation

### Step-by-Step Solution:

1. **Understanding HIV and AIDS**:
- Human Immunodeficiency Virus (HIV) is the virus that causes Acquired Immunodeficiency Syndrome (AIDS). It is crucial to understand that HIV weakens the immune system, making the body more susceptible to infections and diseases.

2. **Sexual Transmission**:
- One of the primary routes of HIV transmission is through unprotected sexual intercourse. This includes vaginal, anal, and oral sex with an infected person. The virus can enter the body through mucous membranes found in the genital area, rectum, or mouth.

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