A: No, science and atheism are two completely different things. Someone can be a scientist and be an atheist or a theist of any sort. There are Christian scientists, Hindu scientists, Muslim scientists, atheist scientists. Science doesn't say anything one way or another about metaphysical issues (subjects having to do with the supernatural, or ideas that are not based in a physical universe); it is concerned solely and exclusively with that which is natural.
Most atheists subscribe to metaphysical naturalism, the idea that the natural world is all there is, period. Scientists subscribe to methodological naturalism, the idea that when trying to figure out how things work, only natural phenomena should be considered. Conflating the two is an error. One can be a scientist, employing methodological naturalism to figure out why volcanoes erupt (weak spots in the mantle allow deep magma to surge to the surface, not "Baal is angry with us") while being, say, a Christian (God created the world such that the mantle has weak spots in it that allow magma to surge to the surface). The two are similar, but different, and conflating the proponents of one with the proponents of the other is a mistake.
Implying that science is the same thing as atheism is like saying "Muslims believe lightning is a natural force, not bolts from an angry god. Science also believes lightning is a natural force, not bolts from an angry god, therefore science is Muslim in nature." Or put another way, it's the error of thinking that because set A and set B have subset C in common, set A equals set B.