How does the diversification of a portfolio change its expected returns and expected risks? Is this in

Question:

How does the diversification of a portfolio change its expected returns and expected risks? Is this in principle any different for internationally diversified portfolios?

Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...