Arare bacterial culture is being grown in a lab. as time passes, the cells multiply in a specific pattern. after 1 day, there is only 1 cell. after 2 days, there are 5 cells. after 3 days, there are 10 cells. after 4 days, there are 16 cells. how many cells will there be after seven days? a. 40 b. 50 c. 60 d. 70