Compared to those of humans, erythrocytes of Frog are

Options

A. without nucleus but with haemoglobin
B. nucleated and with haemoglobin
C. very much smaller and fewer
D. nucleated and without haemoglobin

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks about the comparison of erythrocytes (red blood cells) of frogs with those of humans.

2. **Identify the Characteristics of Human Erythrocytes**:
- In humans, erythrocytes are **enucleated**, meaning they do not have a nucleus. This adaptation allows for more space to accommodate hemoglobin, which is essential for oxygen transport.

3. **Identify the Characteristics of Frog Erythrocytes**:
- In contrast, frogs, being amphibians, have **nucleated erythrocytes**. This means that their red blood cells contain a nucleus.

4. **Compare the Two**:
- Since humans have enucleated erythrocytes and frogs have nucleated erythrocytes, we can conclude that the erythrocytes of frogs are different from those of humans in that they contain a nucleus.

5. **Eliminate Incorrect Options**:
- Option 1 (without nucleus) is incorrect because it describes human erythrocytes, not frog erythrocytes.
- Option 3 (very small and fewer in number) is incorrect as it does not accurately describe the erythrocytes of frogs.
- Option 4 (nucleated and without hemoglobin) is incorrect because frog erythrocytes do contain hemoglobin.

6. **Select the Correct Option**:
- The only correct option is that the erythrocytes of frogs are **nucleated**.

**Final Answer**: Compared to those of humans, erythrocytes of frogs are **nucleated**.

---