chemical contaminations means the contamination of environment by chemical substances like chemical released by industried in water, buring of chemicals in air tjat cause air pollution etc... hope it helsp u
I am guessing the end to this question would be "on"? you never want to leave a fire uncovered and unattended
Sometimes nightmares happen because of what happened on the day before you went to sleep, you might’ve been stressed, you watched a horror movie, or you might have been really scared of something, nightmares also happen because you thought about a lot of creepy things or things that would frighten you before you fell asleep.
Answer:
D
Explanation:
Is there an explanation? I think its pretty self explanatory-
