I would say A) Coevolution because the two species would evolve in response to one another. Flowers and their pollinators must evolve together. For example, if the flower has a mutation that no longer attracts the bumblebees, it will not reproduce. Then the hummingbird would have to find a new food source.
Mitosis, since it involves the process of splitting into two daughter cells.
A receptor refers to a protein molecule, which attains chemical signals from external of a cell. The receptor proteins are categorized by their location. On the other hand, the structural proteins refer to the fibrous proteins. One of the essential activity of the structural protein is to maintain the configuration of the cell.
In the nerve cells, the receptor proteins pick up signals of pain and structural proteins helps in maintaining the shape and configuration of the nerve cell.