Mammals giving rise to immature young ones and nursing them in a pouch are

Options

A. Monotremes
B. Marsupials
C. Primates
D. Carnivores.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about a specific group of mammals that give birth to immature young ones and nurse them in a pouch.

2. **Analyzing the Options**: The options provided are:
- A) Monotremes
- B) Marsupials
- C) Primates
- D) Carnivores

3. **Identifying the Characteristics of Each Group**:
- **Monotremes**: These are egg-laying mammals (e.g., platypus) and do not have pouches.
- **Marsupials**: This group includes mammals that give birth to underdeveloped young, which they carry in a pouch (e.g., kangaroos, koalas).
- **Primates**: This group includes mammals like humans and monkeys, which do not have pouches and give birth to more developed young.
- **Carnivores**: This group includes meat-eating mammals (e.g., lions, tigers) and does not have a specific reproductive strategy involving pouches.

4. **Conclusion**: Based on the characteristics, the only group that fits the description of giving rise to immature young ones and nursing them in a pouch is **marsupials**.

5. **Final Answer**: The correct answer is **B) Marsupials**.

---