Intelligence is basically the ability to learn. It is described as being able to gain knowledge and skills and applying it. So it is not just about knowing things and being able to do things, it also has something to do with being able to "use" knowledge and skills.
With that, the individual is able to understand or like it is mentioned in your question, <u>grasp</u> complex ideas and at the same time, they can use those complex ideas to solve complex problems.
I’m assuming the answer is A. As the parasite population increases, the host population decreases. Parasites often kill their host if not removed so it would make sense for that to be the answer. :)
