The answer is: Mutual Bonds are typically comprised of a mix of Stocks and Bonds.
Mutual funds are a managed portfolio of bonds and stocks. They pool together the capital of many individual investors for the purpose of investing in bonds, stocks, and other assets. Each shareholder, therefore, owns shares of the mutual fund and participates in the gains or losses of the fund. Assume I am an investor and I end up buying Apple stock, what I will buying is part of the ownership of the company and its assets.