Answer:
When we breathe, the air goes through the trachea and bronchi and splits at the tracheas base with one entering each lung. The air divide itself into the bronchioles. Then diffusion happens by swapping the CO2 in the capillaries with O2 in the airsacks. The oxygen hemoglobin gets transported to all of the bodyand the Co2 is exhaled.
Explanation:
Well because it is the amount that the nutritional facts are given on, say you buy a box of donuts, and it says 80 calories that could be for a 2 donuts for 1 for the whole package but knowing the serving size you can base how much you eat etc
