2. Which materials are harmful? When do they become?

Lead, Mercury, Bacteria and poisons.

Explanation:

electronic measurement tools display data on a screen after waiting for several minutes.

while some business owners prefer manual record keeping systems, most businesses use an electronic record keeping system - making it easier to capture information, generate reports and meet tax and legal reporting requirements.

explanation:

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )