Answer:
c. 20.
Step-by-step explanation:
The answer is 20 because on 20 days, 7 colonies of Micro Yo occurs. The data of bacterial growth indicates that population of bacteria increases with the passage of time. This increase occurs due to good environmental conditions for bacteria that allows it to grow and increase their population. So we can say that the growth graph moves in the upward direction with the passage of time or number of days.