You can carry out a test ,
1- take a sample of the air in a test tube
2-add limewater to the test tube
3- result : if it turns milky/cloudy it has microorganisms
4- reason: because every microorganism respires , and so it produces Carbon dioxide .
and limewater is the test to show the presence of Carbon dioxide .
I’m pretty sure it’s B. Relative saying
A balance that performs in an enclosed compartment with no air currents to disturb is called an analytical balance.
Analytical balances are instruments used for precise and determination of mass of matter. They are accurate and very precise instruments. They require a draft-free location on a solid bench that is free of vibrations.
Analytical balances of today are digital and have built in calibration weights to maintain accuracy. Older versions usually require to be manually calibrated using specific standard weights.
