Capillaries<span> are the smallest of the body's blood </span>vessels<span>. They are only one cell thick, and they are the sites of the transfer of oxygen and other nutrients from the bloodstream to other tissues in the body; they also collect carbon dioxide waste materials and fluids for return to the veins.</span>
There are many human relations skills which can help you to more willingly take on a challenging subject. Greater self-confidence is one of those for example.
Being more self-confident enables you to trust more in yourself and therefore to also think you can succeed better with more challenging topics in comparion to the scenario where you don't really think highly about yourself.
I don't think so but I'm not 100% sure
