Different cells have different sizes. Arrange the following cells in an ascending order of their size. Choose the correct option among the followings
i. Mycoplasma, ii. Ostrich eggs
iii. Human RBC, iv. Bacteria

Options

A. i, iv, iii & ii
B. i, ii, iii & iv
C. ii, i, iii & iv
D. iii, ii, i & iv

Answer

To arrange the given cells in ascending order of their size, we need to first identify the approximate sizes of each type of cell mentioned in the question.

1. **Mycoplasma**: This is the smallest known cell, with a size range of approximately 0.1 to 0.5 micrometers (µm).

2. **Bacteria**: Bacterial cells are larger than mycoplasma, typically measuring between 3 to 5 micrometers (µm) in length.

3. **Human RBC (Red Blood Cells)**: Human red blood cells are larger than bacteria, with a diameter ranging from 6 to 8 micrometers (µm).

4. **Ostrich Eggs**: The ostrich egg is the largest cell, with a size that can reach up to 15 centimeters in diameter.

Now, we can arrange these cells in ascending order based on their sizes:

- **1st**: Mycoplasma (0.1 - 0.5 µm)
- **2nd**: Bacteria (3 - 5 µm)
- **3rd**: Human RBC (6 - 8 µm)
- **4th**: Ostrich Eggs (largest cell, up to 15 cm)

Thus, the correct ascending order of the cells based on size is:

**Mycoplasma < Bacteria < Human RBC < Ostrich Eggs**

### Final Arrangement:
1. Mycoplasma
2. Bacteria
3. Human RBC
4. Ostrich Eggs