Answer:
a.
Step-by-step explanation:
Given;
Initial population of bacteria = 1000;
exponential growth for 2 hours;
generation time = 15 minutes;
so,
Bacteria are doubling in every fifteen minute,
In staring, there are 1000 bacteria and after fifteen minutes they become 2000 and after next fifteen minutes bacteria again doubles and become 4000 and so on for next two hours.
so after 2 hours, number of cells of bacteria present are 1000 X 2^8
Total bacterial cells after two hours= 256000.