“At each exhalation, we let go of carbon dioxide and water, which plants ingeniously combine with a touch of sunlight to make their own food and, once again, more oxygen… We breathe each other in and out of existence, one made by the exhalation of the other. With every breath, then, the plant knows the human as herself. At every breath, the human becomes more plant-like than he realizes, and given the right circumstances, he recognizes how he too knows the plant as himself.”

— Monica Gagliano

At the fundamental level, all life on Earth — including plants and humans — share a common ancestor. Both plants and humans evolved from single-celled eukaryotic organisms. This means that, at the molecular level, we still share fundamental biological processes.

Plants having evolved from this eukaryotic organism some millions of years before human beings, were able to evolve and perfect the very processes that our human life is built on.

 Plants are Nature's primary producers. Plants create their own food. For this reason, they are called autotrophic (self-feeding). Ecologist refer to plants as producers because they produce new living (organic) material from non-living (inorganic) materials and are able to take essential chemical building blocks and alchemize them into life sustaining materials. We understand this when we look at the essential chemical building blocks needed for our existence; oxygen, carbon, hydrogen, and nitrogen.

All life on Earth is based on the element carbon. It is found in the bodies of all living things, in the oceans, in the air, and in the Earth itself. In the atmosphere, when combined with oxygen, it forms carbon dioxide. It is in plants, where this carbon dioxide becomes carbohydrates, which then becomes the primary energy source for humans and animals. This process of photosynthesis, also releases oxygen into the air, which we obviously need to breathe and survive.

Although the human body gets most of its hydrogen atoms from drinking water, the essential hydrogen built into our tissues, DNA, and energy systems comes from the food we eat. During the process of photosynthesis, plants split water molecules into hydrogen and oxygen. They keep the hydrogen by locking it into glucose and other organic molecules. Once we consume plants, our metabolism breaks down these plant sugars. This releases the stored hydrogen to create ATP, which is the primary energy currency of all human cells.

Nitrogen is a vital building block for amino acids, which make proteins, and nucleic acids, which makes up our DNA and RNA. As such it is an essential element in the structure of all living things. Although gaseous nitrogen makes up 78 percent of the Earth's atmosphere, plants and animals cannot use it in this form. Through a process of "nitrogen-fixing," bacteria can convert nitrogen in the air directly into nitrates in the soil. Nitrates are soluble in water, and plants are able to take them up through their roots. In turn, humans and animals obtain their nitrogen from plants (or by humans eating animals that eat plants).

As we can see we are not too separate from this planet we dwell. The carbon, nitrogen, hydrogen, and oxygen that makes up our bones, cells, DNA, RNA, tissues, and the list goes on, are the exact same materials that make up Earth's atmosphere. And when Earth produced plants, this creation, would go on to sustain us and are very existence. It's almost as if the plants act as an intermediary between us and Earth itself. And it makes you wonder, in what other ways do they connect us to the realms of this universe.