A:
A standard hard drive utilizes one or more magnetic spinning disks to store data and a read-write head that moves across the disk(s) to access the data. Looks like an ultra-modern version of an old vinyl phonograph and needle. It requires a motor to spin the disks and a mechanical arm to move the read-write head.
A solid state drive stores data within it's circuitry. There are no moving parts.
A portable drive is a hard drive or solid state drive that can be carried around separate from the PC, laptop, etc. that can be attached via cable to almost any PC, laptop, or device.