. Greenhouse gases

are only produced naturally

trap ozone at Earth’s surface

keep Earth cool

absorb heat from the sun

it is prolly d and c and f

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.