One of mercury's properties is that it is a liquid at room temperature. a. reactive b. physical c. chemical

B. physical

Explanation:

Physical properties can be define as the properties which can directly be measured and observed without undergoing the change in the composition of matter. Physical properties include: texture, appearance, color, odor, density, solubility, melting point, polarity,boiling point and many others.  

The mercury remains liquid at room temperature this indicates the physical property of mercury as the composition of the mercury remains the same but the form may change like liquid, solid, or in the form of gas.

"it built up in the atmosphere"

i think thats it, idk, i tried looking for this exact q& a for grad. and idk if i got this question right or sorry if im wrong