Explain how diversification can reduce the risk of a portfolio of assets to below the weighted average

Question:

Explain how diversification can reduce the risk of a of assets to below the weighted average of the risk of the individual assets.

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...