In fruit flies, one genotype for red eyes is written xrxr. the r stands for the dominant allele for red eyes. what does the x stand for?

Compare the composition of the moon's surface with the composition of the earth's surface.

What molecules will be best used to compare different species with the exact same sequence of amino acids? why would two species have the same protein even if the molecules in question is different? (hint: transcription to translation to protein).

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations