ZZ/ZW type of sex determination is seen in

Options

A. platypus
B. snails
C. cockroach
D. peacock

Answer

To determine which organism exhibits ZZ/ZW type of sex determination, we will analyze each of the given options step by step.

### Step 1: Analyze the first option - Platypus
- The platypus is known to have an XX/XY type of sex determination system. In this system, males have XY chromosomes and females have XX chromosomes.
- Therefore, platypus does not exhibit ZZ/ZW type of sex determination.

**Hint:** Remember that platypus has a different sex determination system (XX/XY).

### Step 2: Analyze the second option - Snails
- In snails, sex determination is often influenced by environmental factors, leading to environmentally induced sex determination.
- This means that snails do not have a fixed chromosomal sex determination system like ZZ/ZW.

**Hint:** Consider how environmental factors can influence sex determination in some organisms.

### Step 3: Analyze the third option - Cockroach
- Cockroaches exhibit an XX/XO type of sex determination. In this system, females have two X chromosomes (XX) while males have only one X chromosome (XO), lacking a Y chromosome.
- Thus, cockroaches do not fall under the ZZ/ZW classification.

**Hint:** Recall that cockroaches have a unique sex determination system that does not include Z chromosomes.

### Step 4: Analyze the fourth option - Peacock
- Peacocks (and many birds) exhibit a ZZ/ZW type of sex determination. In this system, males have two Z chromosomes (ZZ), while females have one Z and one W chromosome (ZW).
- This confirms that peacocks are indeed the correct answer to the question.

**Hint:** Remember that in birds, males are typically ZZ and females are ZW.

### Conclusion
After analyzing all the options, the correct answer to the question "ZZ/ZW type of sex determination is seen in" is **peacock**.

**Final Answer:** Peacock (Option 4)