Why eight degrees below zero? (temperature)

[Pepa]

English Grammar Tests, Elementary Level

ESL/EFL Test #82 "Prepositons Test", question 7

The temperature in Washington D.C today is eight degrees ......... zero.

(a) beside
(b) below
(c) behind
(d) between

English Grammar Tests, Elementary Level

ESL/EFL Test #82 "Prepositons Test", answer 7

The temperature in Washington D.C today is eight degrees below zero.

Correct answer: (b) below
_________________________

pls help me..why below?

Pepa

[Yankee]

Hi

The word below can be used when talking about temperatures and other things that are measured to say that something that is under or less than a certain point.

For example, you can also say:

It is below freezing today. (i.e. The temperature is less than 32 degrees F.)
His work is below average. (i.e. The quality of his work is less than average.)

Amy