Can someone please help me with my chemistry test it’s all multiple choice. i just have a few questions!!!

GUYS PLEASE. I HAVE TO SUBMIT THIS IN A FEW:(

I’LL GIVE A BRAINIST:)

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

Why is nh3 classified as a polar molecule

The yearly amounts of carbon emissions from cars in belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 5.8 gigagrams per year. find the probability that the amount of carbon emissions from cars in belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year. a. 0.340 b. 0.660 c. 0.167 d. 0.397