in a petri dish, a certain type of bacterium doubles in number every 30 minutes. there were originally 16, or 2^4, bacteria in the dish. after 150 minutes, the number of bacteria has doubled 7 times, multiplying by 2^7. Now the population of bacteria is 2^4 • 2^7. Expressed as a power, how many bacteria are in the petri dish after 150 minutes? A. 2^28 B. 2^11 C.4^11 D.2^7