Final answer:
The time it takes for complementary strands to reanneal depends on the length of the DNA strands, the temperature of the solution, and the concentration of DNA in the solution.
Step-by-step explanation:
The time it takes for complementary strands to reanneal depends on all of the above options: the length of the DNA strands, the temperature of the solution, and the concentration of DNA in the solution.
When the strands of DNA are separated, they can reanneal or come back together when the conditions are favorable. The length of the DNA strands affects the time it takes for reannealing because longer strands take more time to find their complementary sequences. The temperature of the solution also plays a role because higher temperatures speed up reannealing, while lower temperatures slow it down. Additionally, the concentration of DNA in the solution affects the reannealing process because higher concentrations of DNA increase the likelihood of complementary strands finding each other.