In humans, the sex chromosome complement is

Options

A. XX-XY
B. XX-XO
C. ZZ-ZO
D. ZW-ZZ

Answer

To solve the question regarding the sex chromosome complement in humans, we will analyze the options provided and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding Human Sex Chromosomes**:
- In humans, there are two types of sex chromosomes: X and Y.
- Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

2. **Analyzing the Options**:
- **Option 1: XX and XY**:
- This option is correct. It accurately represents the sex chromosome composition in humans.
- **Option 2: XXXO**:
- This option is incorrect. The XXXO system is found in grasshoppers, where females have XX and males have XO (one X and no second sex chromosome).
- **Option 3: ZZ and ZO**:
- This option is also incorrect. The ZZ/ZO system is seen in some insects like butterflies and moths, where ZZ represents males and ZO represents females.
- **Option 4: ZW and ZZ**:
- This option is incorrect as well. The ZW/ZZ system is found in birds, where ZW represents females and ZZ represents males.

3. **Conclusion**:
- After analyzing all the options, the correct answer is **Option 1: XX and XY**, as it correctly describes the sex chromosome complement in humans.

### Final Answer:
The sex chromosome complement in humans is **XX for females and XY for males**.

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