What best describes why mortgage funds generally have less sensitivity to changes in interest rates...

Mortgage funds have lower interest rate sensitivity than bond funds because mortgage rates change less frequently, and interest is paid monthly rather than semi-annually, reducing the impact of rate changes. The feedback from the document states:

"Interest rate sensitivity is expected to be lower for mortgage funds than for bond funds for two reasons. First, mortgage rates change much less frequently than interest rates on bonds… Second, mortgages by nature have less interest rate risk than bonds. The reason, in part, is that interest on mortgages is paid monthly, while interest on bonds is paid semi-annually."