Bhasker Soni

Capillaries connect the arterial system — which includes the blood vessels that carry blood away from your heart— to your venous system Your venous system includes the blood vessels that carry blood back to your heart.

An artery is a vessel that carries blood away from the heart and toward other tissues and organs. Arteries are part of the circulatory system, which delivers oxygen and nutrients to every cell in the body.

You want to master what? There are many subjects to study. If you are asking about subjects till class 12, then you can master it very quickly, and you can learn more about it. Mastering any subject is not about merging or solving the MCQs, but mastering understands the more profound meaning. Understand the difference between mastering for entrance and mastering for more understanding and explaining.
If you want to master any subject, the first step is always to understand the basics. The real basic, ask the same question, ask a baseless question for any topic and try to answer it, you will be more transparent with your concepts. 2nd step is to practice numerical and problems related to it. Try to teach others your learning that will build better self-confidence. Lastly, revise periodically.