A spore of Spirogyra sp. after resting period is

Options

A. Diploid
B. Haploid
C. Zoospores
D. Aplanospores.

Answer

To solve the question "A spore of Spirogyra sp. after resting period is?", we can follow these steps:

### Step 1: Understand the Life Cycle of Spirogyra
- Spirogyra is a filamentous green alga that reproduces sexually by forming zygospores. The life cycle includes both haploid and diploid stages.

**Hint:** Review the life cycle of Spirogyra, focusing on the stages involving spores.

### Step 2: Identify the Type of Spore
- The spore formed in Spirogyra is called a zygospore, which is the result of the fusion of two haploid gametes. This zygospore is diploid.

**Hint:** Recall the difference between haploid and diploid spores in the context of Spirogyra.

### Step 3: Understand the Resting Period
- The zygospore can withstand harsh conditions due to its thick wall and remains dormant (resting period) until favorable conditions arise, such as the rainy season.

**Hint:** Consider what happens to the zygospore during the resting period and what triggers its germination.

### Step 4: Germination of Zygospore
- Upon the arrival of favorable conditions, the zygospore undergoes meiosis. The diploid zygospore divides meiotically to produce four haploid nuclei. Out of these, three nuclei degenerate, leaving one functional haploid nucleus.

**Hint:** Focus on the process of meiosis and how it affects the ploidy level of the spore after the resting period.

### Step 5: Conclusion
- After the resting period, the zygospore of Spirogyra, upon germination, becomes a haploid spore.

**Hint:** Summarize the key points about the transformation of the zygospore after the resting period.

### Final Answer
The spore of Spirogyra sp. after the resting period is **haploid**.