How can 20-year-olds enhance their intelligence?

As others have mentioned, the brain is similar to any other muscle in that it becomes stronger with exercise. One way to exercise the brain is by following these steps:

1. Choose a question - Select a question from any field that interests you, and ensure that the answer is verifiable. The question does not need to be overly complicated; it could be about something from your daily life. For example:

- How many cars are there in the US? (General)

- What is the coefficient of friction of a slide? (Physics, Mechanics)

- What is the evolutionary purpose of facial hair? (Biology, beauty?)

2. Create a hypothesis - Develop your own theory or hypothesis to answer the question. You may need to make assumptions or estimate numbers to support your theory.

3. Verify assumptions - Research and verify the assumptions you made while creating your theory. Review related materials and ensure that your assumptions do not contradict any existing information.

4. Modify - Make adjustments to your theory or answer based on the verification of your assumptions. Repeat steps 2-4 as necessary.

5. Final answer - Reach a final answer based on your modified theory.

6. Verify and learn - Verify your answer and determine its accuracy. If it is correct or close to correct, celebrate your achievement. If not, analyze the mistakes you made and learn from them.

This method is similar to the scientific process of reaching conclusions. It enhances reasoning skills and promotes learning through the exploration and discovery of new information.