Number of lateral hearts in Pheretima are

Options

A. 8
B. 12
C. 16
D. 4

Answer

To determine the number of lateral hearts in Pheretima, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Recognize that Pheretima is a genus of earthworms. This is important as it sets the context for the anatomical features we need to consider.

2. **Understand the Heart Structure**: In Pheretima, there are structures known as pulsatile hearts. These are contractile structures that help in pumping blood.

3. **Locate the Segments**: The lateral hearts are located in specific segments of the earthworm. According to the information, they are found in segments 7, 9, 12, and 13.

4. **Count the Pairs**: It is mentioned that there are 4 pairs of these pulsatile hearts. Since each pair consists of 2 hearts, we calculate the total number of hearts.

5. **Calculate the Total**: Multiply the number of pairs (4) by 2 (since each pair has 2 hearts):
\[ 4 \text{ pairs} \times 2 = 8 \text{ hearts} \]

6. **Conclusion**: Therefore, the total number of lateral hearts in Pheretima is 8.

### Final Answer:
The number of lateral hearts in Pheretima is **8**.

---