Type of fertilisation in Chondrichthyes and osteichthyes is____

Options

A. External and internal respectively
B. Internal and extranal respectively
C. Internal only
D. External only

Answer

To answer the question regarding the type of fertilization in Chondrichthyes and Osteichthyes, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding Chondrichthyes**:
- Chondrichthyes are a class of cartilaginous fishes, which include sharks and rays.
- They have a skeleton made of cartilage rather than bone.

2. **Fertilization in Chondrichthyes**:
- The type of fertilization that occurs in Chondrichthyes is **internal fertilization**.
- In internal fertilization, the male deposits sperm inside the female's body, leading to the development of embryos either through live birth (ovoviviparous) or through eggs (oviparous). Some species may also be viviparous.

3. **Understanding Osteichthyes**:
- Osteichthyes are known as bony fishes and have a skeleton made of bone.
- They represent a diverse group of fish.

4. **Fertilization in Osteichthyes**:
- The type of fertilization that occurs in Osteichthyes is **external fertilization**.
- In external fertilization, females release eggs into the water, and males release sperm simultaneously, allowing fertilization to occur outside the female's body.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the type of fertilization in Chondrichthyes is **internal** and in Osteichthyes is **external**.
- This leads us to the answer: **Option B: internal and external respectively**.