**Respiration**

Respiration is the process by which living organisms, including humans and animals, take in oxygen and release carbon dioxide. It is a vital process for the survival of organisms as it provides the necessary energy for various bodily functions.

During respiration, organisms break down glucose (a type of sugar) in the presence of oxygen to produce energy, carbon dioxide, and water. The oxygen is obtained from the air through breathing, and the carbon dioxide is released into the air as a waste product.

**Explanation:**

Respiration plays a significant role in increasing the amount of carbon dioxide in the air. Here's how it happens:

1. **Inhalation**: During inhalation, organisms take in oxygen-rich air into their lungs. Oxygen is then transported to the cells through the bloodstream.

2. **Cellular Respiration**: Inside the cells, glucose combines with oxygen in a process called cellular respiration. This process occurs in the mitochondria, which are the energy-producing organelles of the cell.

3. **Energy Production**: During cellular respiration, glucose molecules are broken down into carbon dioxide, water, and energy. The energy produced is used for various metabolic activities and to sustain life.

4. **Carbon Dioxide Release**: As a result of cellular respiration, carbon dioxide is produced as a waste product. This carbon dioxide is then transported back to the lungs through the bloodstream and released into the air during exhalation.

5. **Exhalation**: During exhalation, organisms expel the carbon dioxide-rich air from their lungs, releasing it into the surrounding environment.

Therefore, respiration is the process that increases the amount of carbon dioxide in the air. It is essential to maintain a balance of carbon dioxide in the atmosphere as it is a greenhouse gas that contributes to the Earth's climate. Excessive amounts of carbon dioxide can lead to global warming and other environmental issues.

Respiration is the correct answer because we breath in oxygen and breath out carbon dioxide which increase the amount of carbon dioxide in the air