Which statement is an example of variation within a species? picture attatched. A. Birds have wings, and so do butterflies.
B. Some squirrels are gray, and others are brown,
C. A lion roars and so does a tiger.
D. Dinosaurs are extinct but we know that they existed because of fossils.

There are four nitrogenous bases that make up dna. the two pyramidines are thymine and cytosine. the two purines are adenine and guanine. these bases pair in a very specific way. adenine - thymineguanine - cytosine i remember it like this: a tall, good cat.

Mars and earth have quite a few things in common. both are  terrestrial planets, both are located within the sun’s  habitable zone, both have  polar ice caps, similarly  tilted axes, and similar  variations in temperature. and according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that mars once had a  dense atmosphere  and was covered with  warm, flowing water.