Answer in one word/a few words.Addition of harmful substances to the air as a result of human activities
Answer in one word/a few words.Process that results in the better supply of oxygen into the lungs
Answer in one word/a few words.Process of taking in oxygen and giving out carbon dioxide
Answer in one word/a few words.Spongy bag-like structures of the respiratory system
Answer in one word/a few words.An organ that is also called throat or trachea
