In carbon dioxide (co2), there are two oxygen atoms for each carbon atom. each oxygen atom forms a double bond with carbon, so the molecule is formed by two double bonds. two double bonds means that the total number of electrons being shared in the molecule is

Two double bonds means that it is an element, or a compound. 

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait. 

Scans the skeleton into a facial reconstruction software.