Final answer:
The causative agent of mumps is the Paramyxovirus, which infects the parotid glands. It contains hemagglutinin and neuraminidase spikes and a fusion protein on its surface.
Step-by-step explanation:
The causative agent of mumps is the Paramyxovirus. This virus has an envelope with hemagglutinin and neuraminidase spikes and contains a fusion protein on the surface that helps it fuse with the host cell plasma membrane. Mumps is an infection of the parotid glands, which are the largest of the three pairs of salivary glands.