It would be difficult to find the ideal CO2 level with a low light intensity because the plant will have a difficult time trying to survive.
The 7 (sometimes 8) characteristics of life are:
1. living things are composed of cells
2. living things have different levels of organization
3. living things metabolize (i.e. use energy)
4. living things respond to their environment
5. living things grow
6. living things reproduce
7. living things adapt to their environment
(some sources include) 8. living things have genetic material
Viruses do not metabolize, they do not grow, they do not adapt to their environment, and they cannot reproduce independently; viruses require host cells to reproduce and perform the other functions that give them the appearance of aliveness.
Oxygen enters the blood in the A. Bronchi.
