When cells of a 15-celled filament of spirogyra participate in indirect lateral conjugation, the maximum number of zygospores produced is

Options

A. 15
B. 14
C. 8
D. 7

Answer

To solve the question regarding the maximum number of zygospores produced when cells of a 15-celled filament of Spirogyra participate in indirect lateral conjugation, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Spirogyra**:
- Spirogyra is a filamentous green alga that reproduces sexually through a process called conjugation.

2. **Identify the Type of Conjugation**:
- The question specifies "indirect lateral conjugation." In this type of conjugation, pairs are formed between adjacent cells of the same filament.

3. **Determine the Number of Cells Participating**:
- In a 15-celled filament, we can pair the cells for conjugation. Each pair consists of two adjacent cells.

4. **Calculate the Number of Pairs**:
- Since we have 15 cells, we can form pairs from these cells. Each pair will consist of 2 cells.
- The maximum number of pairs that can be formed from 15 cells is calculated as follows:
- The first 14 cells can be paired (1 with 2, 3 with 4, ..., 13 with 14), which gives us 7 pairs.
- The 15th cell remains unpaired.

5. **Determine the Number of Zygospores Produced**:
- Each pair of cells produces one zygospore.
- Since we have 7 pairs, this results in 7 zygospores being produced.

6. **Final Answer**:
- Therefore, the maximum number of zygospores produced from a 15-celled filament of Spirogyra participating in indirect lateral conjugation is **7**.