Introduction:
The balance of gases in the air refers to the natural composition of gases present in the Earth's atmosphere. This balance is essential for maintaining a healthy and stable environment. However, certain human activities can disrupt this balance and lead to environmental issues such as air pollution and climate change.

Explanation:
- Cutting down trees and forests: The cutting down of trees and forests has a significant impact on the balance of gases in the air. Trees play a crucial role in the process of photosynthesis, where they absorb carbon dioxide (a greenhouse gas) and release oxygen. By cutting down trees, the amount of carbon dioxide in the atmosphere increases, disturbing the balance of gases.

- Releasing polluting gases into the air: The release of polluting gases, such as carbon dioxide, sulfur dioxide, and nitrogen oxides, into the air has a detrimental effect on the balance of gases. These gases are often emitted from industrial processes, power plants, and vehicles. They contribute to air pollution and can lead to health problems and climate change.

- Releasing smoke from the vehicles: The release of smoke from vehicles is another activity that disturbs the balance of gases in the air. Vehicle emissions contain pollutants such as carbon monoxide, nitrogen oxides, and particulate matter. These pollutants can have adverse effects on air quality and human health.

- Growing trees: Growing trees, on the other hand, does not disturb the balance of gases in the air. As mentioned earlier, trees absorb carbon dioxide during photosynthesis and release oxygen. By planting and growing trees, we can help offset the carbon dioxide emissions and restore the balance of gases in the air. Trees also provide shade, habitat for wildlife, and contribute to the overall well-being of the environment.

Conclusion:
In conclusion, cutting down trees and forests, releasing polluting gases into the air, and releasing smoke from vehicles all disturb the balance of gases in the air. However, growing trees helps to restore this balance by absorbing carbon dioxide and releasing oxygen. Therefore, the correct answer is option 'C' - growing trees.

Sun is a renewable source of energy which provides heat and light. The source of solar energy is the sun.