The number of chloroplast varies from 1 per cell in …a… to …b… per cell in the mesophyll.

Options

A. a`-`Chlorella , b`-`15 to 20
B. a`-`Chlamaydomonas, b`-`20 to 40
C. a`-`Chlamydomonas, b`-`15 to 20
D. a`-`Chlamydomonas, b`-`10 to 40

Explanation

To solve the question about the number of chloroplasts in different cells, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism with 1 Chloroplast**:
- The question states that there is an organism with 1 chloroplast per cell. This organism is **Chlamydomonas**, which is a type of green algae.

2. **Determine the Range of Chloroplasts in Mesophyll Cells**:
- Next, we need to find out how many chloroplasts are present in mesophyll cells of green plants. Mesophyll cells are known to have a higher number of chloroplasts compared to other cells in plants.

3. **Research the Typical Number of Chloroplasts in Mesophyll**:
- In mesophyll cells, the number of chloroplasts typically ranges from **20 to 40** per cell. This is significantly higher than the single chloroplast found in Chlamydomonas.

4. **Fill in the Blanks**:
- Based on the information gathered:
- **a** = Chlamydomonas (1 chloroplast per cell)
- **b** = 20 to 40 (chloroplasts per cell in mesophyll)

5. **Final Answer**:
- The completed statement is: "The number of chloroplasts varies from 1 per cell in **Chlamydomonas** to **20 to 40** per cell in the mesophyll."