A good answer might be:

Both. Double precision numbers have more bits for the exponent (so the range of values is increased) and more bits in the mantissa (so the precision is increased).

MIPS Floating Point

Floating point on MIPS was originally done in a separate chip called coprocessor 1 (also called the FPA for Floating Point Accelerator). Modern MIPS chips include floating point operations on the main processor chip. But the instructions sometimes act as if there were still a separate chip.

MIPS has 32 single precision (32 bit) floating point registers.

The registers are named $f0 – $f31
$f0 is not special (it can hold any bit pattern, not just zero).
Single precision floating point load, store, arithmetic, and other instructions work with these registers.

QUESTION 2:

(Memory Test: ) Why is $f0 not hard-wired to floating point zero, like register $0 is hard-wired to integer zero?