What is the difference between double and single stranded rna and
the difference between positive and negative rna
(all relating to viruses)

In DNA it is called "sense" and "antisense" - this is just which way the DNA twists - like which way the thumb sticks out of your hand is based on which hand it is... the DNA in a nucleus that is "read" (transcribed) into mRNA is "antisense" and for this reason the mRNA that results (when the DNA is translated) is called "sense" -because it is like a backwards imprint... in viri (the "correct" Latin/scientific for "viruses") positive sense means that the viral RNA looks to the cell just like mRNA coming from the nucleus... so it can be *translated* (by the ribosome) into amino acid sequences used to make a protein... when a virus infects a cell, it will use one type of RNA or the other (if it is an RNA virus anyway) to get the cellular machinery (the ribosome) to make proteins that help the virus, and often harm the cell... if the virus releases negative sense RNA it has to be copied (and thus reversed) into positive sense RNA by a different cellular "machine" called RNA polymerase before the ribosome can read and thus translate it into aa sequence.

This movement is also referred to as  glacial plucking

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.