When the mercury level in a barometer decreases that atmospheric pressure has

increases

Explanation:

The barometer is a device that uses mercury in order to work and be able to measure the air pressure. The mercury reacts to the air pressure, so it either goes up or down. If the mercury goes down, that means that it is pressed more, thus the air pressure has increased, or rather is higher. If the mercury is lifting up, that means that there is less pressure from the air, thus the air pressure has declined, or rather is lower. It is a simple device that manages to do a very important job, and it is one of the most important devices used by the meteorologists for telling the current weather conditions, as well as predicting them for the next few days.

the answer is   c.) 1575 j.

explanation:

it is reliable if two scientists recorded it