Answer:
(E). 19
Step-by-step explanation:
Let original population of each colony be P.
We have been given that a certain bacteria colony doubles in size every day, so bacteria colony is growing exponentially. After x days, the population of bacteria would be:
[tex]P(2)^x[/tex]
The population after 19 days will be [tex]P(2)^{19}[/tex] for each colony.
The total population of both the colonies at that point will be [tex]P(2)^{19}+P(2)^{19}=2P(2)^{19}=P(2)^{20}[/tex] which is what the habitat's limit is.
Therefore, it will take 19 days for two bacteria colonies to reach the habitat's limit and option E is the correct choice.