PLEASE HELP! I am stuck and this is due in a couple of hours! Please don’t type in links or recite the alphabet! Thank you! Also please try your best to explain your answer!

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

the answer is option a.

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)