They come from the atmosphere, since plants use carbon dioxide to produce carbohydrates :)
Viruses are not considered living because they cannot survive without a host organism, and they do not exhibit the characteristics of life.
A general ballpark how one can predict the way how evolution will work in the future would be by thinking about the requirement of a certain area or environment and which changes would be necessary and relevant for any organism to thrive with its new changes.
This could help people speeden up this process by enabling organisms to develop such traits faster, as well as ourselves.
Invasive species depopulating Native species.
When stomata are open, carbon dioxide enters the plant through stomata. Carbon dioxide is necessary for the process of photosynthesis in which it is converted together with water into oxygen and glucose. For most plants, it is necessary that stomata are opened during the day when there is a lot of Sunlight also necessary for the process of photosynthesis.
However, some plants from the arid locations have <span>stomata closed during the day, so they reduce water loss that way. In the night when is colder, stomata open and carbon dioxide enters through stomata. </span>
