Final answer:
If cells double with each generation, there would be 8192 cells after 12 hours when starting with 2 cells initially.
Step-by-step explanation:
The number of cells doubles with each generation in exponential growth.
In this case, if 2 cells are present initially and the number of cells increases to 36 after 7 hours, we can calculate the number of cells after 12 hours by finding the number of generations that have occurred.
Since each hour represents 2 generations (cells divide every 30 minutes), after 12 hours, there would be 2^(12/0.5) = 8192 cells present.