Why forest is called green lungs?

 Plants release oxygen through the process of photosynthesis. The plant help to provide oxygen for animal respiration. They also maintain the balance of carbondioxide in the atmosphere .That is why forest is called green lungs.

 And other answer for my question is:-

Forest is called the green lungs because it consists of trees whch have green leaves .The leaves take in carbon dioxide and gives out oxygen.Thus they purify the air.

Which is right?Tell me please.

BEACAUSE IT HAS GREEN COLOUR AND PRODUCES OXYGEN BY WHICH WE CAN LIVE

The plants release oxygen through the process of photosynthesis. The plants provide oxygen for animal respiration and also absorb carbon dioxide from the atmosphere. In this way plants help in maintaining the balance of oxygen and carbon dioxide in the atmosphere. Forests also influence climate, water cycle and air-quality. That is why forests are called “green lungs”.

The plants produce large amounts of Oxygen and absorbs large amounts of Carbon Dioxide.Thus,it maintains the balance of Oxygen and Carbon Dioxide in the atmosphere.This is why forests are called the green lungs.

the plants inhale carbondioxide exhaled by other animals. as same as our lungs purify the air, the green plants in a forest, do this task. so, forests are called as the green lungs of nature.