DENDROLOGY

Detailed explanation-1: -Forests serve as green lungs. Plants and trees give out oxygen and take carbon dioxide, during the process of photosynthesis. They help in the respiration of human beings and maintain the concentration of oxygen and carbon dioxide.

Detailed explanation-2: -noun. an area of parkland within a town or city, considered in terms of the healthier environment it provides.

Detailed explanation-3: -The human lungs absorb oxygen and give out carbon dioxide. Similarly, the Amazon rainforest absorbs the carbon dioxide from the atmosphere and releases oxygen in a very large amount.