A Those genes which are present on "Y" chromosomes of human beings are called holandric genes.
R Holandric genes are present both in men as well as women.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "those genes which are present on 'Y' chromosomes of human beings are called holandric genes."
- Holandric genes are indeed located on the Y chromosome. This is a true statement.

2. **Understanding the Reason:**
- The reason states that "holandric genes are present both in men as well as women."
- Holandric genes are specifically linked to the Y chromosome, which is only present in males (XY chromosome pair). Females have two X chromosomes (XX) and do not possess a Y chromosome. Therefore, this statement is false.

3. **Evaluating the Relationship:**
- The assertion is correct because it accurately describes holandric genes as being located on the Y chromosome.
- The reason is incorrect because it claims that these genes are present in both men and women, which is not true.

4. **Conclusion:**
- Since the assertion is correct and the reason is incorrect, the correct option is: "Assertion is correct, reason is wrong."