b. atomic radius
as it goes increases when it goes down the periodic table, it decreases when going left to right. all the others decrease while going down the table.
if it helps you to remember, everything here besides atomic radius has an e in it. and if you make a connection with it to electrons, they are negative, which means they would decrease going down the table. so e=decrease while going down
thats what helped me remember it, so i hope this technique could help you too.
Nothing is less dense than gas. gas is the least dense form of matter.
Answer: A.Light travels in a straight line., B.Light behaves in a predictable way. , D.Light curves around corners or obstructions
-Hope this helps<3
I think the answer is A, ozone depletion
