Answer:
On the one hand the human being when breathing consume oxygen and returns carbon dioxide to the environment, which for human respiration would be waste, instead the absorbent plant said carbon dioxide to transform it into nutrients through photosynthesis and as a danger releases oxygen, the which as we said before is used by the human being in his breathing. This concludes a sustainability cycle with zero waste.
Step-by-step explanation:
Photosynthesis is a process that develops in two stages:
Light reactions: it is a light-dependent process (clear stage), it requires light energy to manufacture ATP and NADPH reduced energy carrier molecules, to be used in the second stage.
Calvin-Benson cycle: it is the independent stage of light (dark stage), the products of the first stage plus CO2 are used to form the C-C bonds of carbohydrates. Dark stage reactions usually occur in the dark if energy transporters from the light stage are present. Recent evidence suggests that the most important enzyme of the dark stage is indirectly stimulated by light, if so the term would not be correct to call it "dark stage". The light stage occurs in the grana and the dark one in the stroma of the chloroplasts.
Human breathing
In breathing, a vital process for life, the oxygen from the inhaled air enters the blood, and carbon dioxide - a waste gas from the metabolism of nutrients - is exhaled into the atmosphere.
The exchange of these gases takes place when the air reaches the pulmonary alveoli. These small sacs are surrounded by blood capillaries. The air diffuses through these cells to reach the interior of the blood capillaries, which transport oxygen-rich air to the heart to be distributed throughout the body. At the same time, in the alveoli the gaseous carbon dioxide diffuses from the blood into the lung and is exhaled.