DENDROLOGY

Detailed explanation-1: -During photosynthesis, plants take in carbon dioxide and give out oxygen as a byproduct. The oxygen given out is utilized by humans and other animals for carrying out their own cellular functions.

Detailed explanation-2: -During respiration, both energy and a gas known as carbon dioxide are produced. When we breathe out, the carbon dioxide that is produced is released into the air. Plants such as trees, on the other hand, can take in this carbon dioxide, which is unusable for humans, and use it to produce their own energy.

Detailed explanation-3: -Most life on Earth depends on photosynthesis. The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O2) and chemical energy stored in glucose (a sugar).