Answer:
a)
Based on the data for the group of cells, among the four proteins, protein p16 does not appear to play a role in blocking cell cycle entry by fibroblasts. The evidence for this is in group 7, where, in the absence of the other proteins the p16 presence has helped the replication of DNA almost as good as the growth in the 10% serum.
In the other groups (3 to 6) the presence of any other protein has always inhibited the DNA replication compared to the fibroblast in 10% serum.
b)
Groups 4 to 7 have higher chance of including cells undergoing mitosis as they are showing more DNA replication compared to the group 1 which has 0% serum. In this group since it has been cultured for 48 hours in the absence of serum (serum-starvation), they stop dividing and enter the G0 stage of the cell cycle.
c)
The data here would provide the crucial information on which protein is required to induce the cells to enter the cell cycle. To recover from an injury the cells should divide and repair the wound, this will happen through stimulating the cell with the required protein. It would also shed light on which protein would inhibit the cells from entry into the cell cycle.
Note: Figure is added in the attachment section
