Answer:
Intelligence
Step-by-step explanation:
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, grasp complex ideas and at the same time, they can use those complex ideas to solve complex problems.