the only good answer is
A. plant growth would decrease
I believe in both carbon dioxide and oxygen
Answer:
The most appropriate answer would be a stem cell.
Stem cells are the undifferentiated cells which have the capability to divide to give rise to more number of the same type of cell.
In addition, these cells have a capability to develop in a particular cell type or specialized cell by the process of cell differentiation.
For example, the embryonic stem is undifferentiated pluripotent cells which are capable of giving rise to almost all types of cells of the body.