ZO-ZZ type of sex determination is

Options

A. opposite of XX-XO type
B. opposite of XX-XY
C. opposite of ZZ-ZN type
D. gynander

Answer

**Step-by-Step Solution:**

1. **Understanding ZO-ZZ Sex Determination:**
- The ZO-ZZ type of sex determination is a system found in certain insects, such as butterflies and moths. In this system, males are homogametic (ZZ) and females are heterogametic (ZO).

2. **Identifying the Opposite Systems:**
- The question asks which of the provided options is the opposite of the ZO-ZZ system. To determine this, we need to understand the characteristics of the other types of sex determination mentioned.

3. **Analyzing the Options:**
- **Option A: Opposite of XXXO type** - In the XXXO system, females are homogametic (XX) and males are heterogametic (XO).
- **Option B: Opposite of XXXY type** - In the XXXY system, females are homogametic (XX) and males are heterogametic (XXY).
- **Option C: Opposite of ZZZN type** - In the ZZZN system, males are homogametic (ZZZ) and females are heterogametic (ZN).
- **Option D: Gananda** - This option does not refer to a recognized sex determination system.

4. **Determining the Correct Answer:**
- The ZO-ZZ system is characterized by males having two sex chromosomes (ZZ) and females having one (ZO). The XXXO system is characterized by females having two sex chromosomes (XX) and males having one (XO). Therefore, the ZO-ZZ system is indeed the opposite of the XXXO system.
- Thus, the correct answer is **Option A: opposite of XXXO type**.

5. **Conclusion:**
- The ZO-ZZ type of sex determination is opposite of the XXXO type.

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