If the level of water in the eudiometer is below that in the cylinder, is the pressure in the eudiometer higher or lower than the atmospheric pressure?

lower than the atmospheric pressure

Explanation:

An eudiometer have a graduated glass tube , where the mixture of the gases react with the electric spark , which helps to measure the change in the volume of the gases , during the process of the chemical reaction .

From the question ,

when the water level in the eudiometer is below that in the cylinder , then , the pressure in the eudiometer will be lower than the pressure of the atmosphere .

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.