The correct answer is (A) Chromosomes.
The color of the horse coat is determined by chromosomes. The genes present on the chromosomes is responsible for the coat color of horse. The dominant coat color of the horse is transferred to the horse from its parents. This is inherited pattern and the coat color can be black, white, brown, etc.
Explanation:
because the tilt of the earth on its axis
What this student is doing is collecting data. So, he wants to check how many life forms there are in the waters nearby. In order to do so, he has to take a sample, and look at it through a microscope so as to determine the number. So, he collected a sample which is his data. He is not drawing conclusions yet, but rather counting these organisms. He is not making a peer review - his peers aren't even mentioned here. He is not forming a hypothesis because he is just counting at this point.
