Air is classified as a mixture. What statement must be true about air? (4D) a.) Air has a composition that is always the same mixture of elements and compounds.
b.) Air is made up of atoms of several different elements that are chemically combined.
c.) Air is made up of atoms of one element.
d.) Air is two or more elements or compounds that are not chemically combined.

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

The reactions of photosynthesis occur in the of plant cell? a.mitochondria. b. lysosomes. c. chloroplasts. d. chlorophyll

An atomic nucleus is composed ofa)protons.b)protons and neutrons.c)protons and electrons.d)protons, neutrons, and electrons.