Answer:
The temperature at midnight was -2 degrees Celsius.
Explanation:
At 7:00 am, the temperature was 8 degrees Celsius.
Now, given that at the midnight the temperature was 10 degrees Celsius lower or it fell 10 degrees, so we will subtract 10 degrees from 8 degrees.
Means, the temperature fell 8 degrees to get to zero and then 2 degrees more below from zero.

So, we get -2 degrees Celsius.
Therefore, the temperature at midnight was -2 degrees Celsius.