Genesis 6:5
The Lord saw how great the wickedness of the human race had become on the earth, and that every inclination of the thoughts of the human heart was only evil all the time.

Genesis 24:45
"Before I finished praying in my heart, Rebekah came out, with her jar on her shoulder. She went down to the spring and drew water, and I said to her, 'Please give me a drink.'

Genesis 34:8
But Hamor said to them, "My son Shechem has his heart set on your daughter. Please give her to him as his wife.

When you are not able to take enough oxygen, I think that you will get tired because you cannot make energy without oxygen and if it keep, you will die.

When you exercise, your breathing become fast, because your heart is moving fast to get energy for the exercise.

I think that alveoli is most important part of the respiration because we exchange gases.

Breathing is to get air and exhale. Respiration is process of passing oxygen to our body.