Plants use oxygen in manufacturing their own food.

Too much carbon dioxide in the atmosphere may be responsible for greenhouse effect.

During respiration, people and animals take in carbon dioxide.

Plants produce oxygen as a result of photosynthesis.

Plants release 430-470 billion tons of oxygen during transpiration.

During respiration, people and animals release oxygen as their by-product.

Trees are important in the production and release of oxygen in the atmosphere.

In photosynthesis, plants manufacture their own food.

During photosynthesis, plants absorb solar energy, carbon dioxide in the air, water and other elements from the soil to manufacture their own food.