Ingenhousz in an experiment showed that in bright sunlight, small bubbles were formed around the green parts of the plant, while in the dark, they did not. He identified these bubbles to be of

Options

A. `CO_(2)`
B. `H_(2)O`
C. `O_(2)`
D. `H_(2)`

Explanation

### Step-by-Step Solution:

1. **Understanding Ingenhousz's Experiment**: Jan Ingenhousz conducted experiments with aquatic plants to investigate the process of photosynthesis. He observed the behavior of these plants under different lighting conditions.

2. **Observation in Bright Sunlight**: During his experiments, Ingenhousz noted that when the aquatic plants were exposed to bright sunlight, small bubbles formed around the green parts of the plants. This indicated some form of gas release.

3. **Observation in Darkness**: Ingenhousz also observed that when the same plants were kept in the dark, no bubbles were formed. This suggested that the gas release was dependent on the presence of light.

4. **Identifying the Gas**: Ingenhousz concluded that the bubbles produced in sunlight were not just any gas but specifically identified them as oxygen (O2). This was a significant finding as it linked the process of photosynthesis to the release of oxygen.

5. **Conclusion**: Ingenhousz concluded that the green parts of the plants purify the air by releasing oxygen, but this process only occurs in the presence of sunlight. Thus, the bubbles he observed were identified as oxygen.

### Final Answer:
Ingenhousz identified these bubbles to be **oxygen (O2)**.

---