The answer to your question is <span>B. Natural selection acted on the variation that was present in the population.
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<span>First determining if the cells in the tumor have common and the unique genetic and biochemical marker and if they are present, that would clearly mean that they all were created from a initially mutated cell and formed the marker and these are considered as monoclonal. If that is not the case and cells do not have a common origin, these are called as polyclonal.</span>
I think the answer to this is E
Earth had essentially no atmosphere when it originated 4.6 billion years ago from a heated mixture of gases and minerals. The ground had melted on it.
An atmosphere developed when Earth cooled, primarily from gases released by volcanoes. It contained methane, hydrogen sulfide, and ten to 200 times as much carbon dioxide as the atmosphere we are surrounded by today. The Earth's surface began to cool and solidify after roughly 500 million years, allowing water to accumulate there. Although life on Earth continued to develop and diversify, such periods of expansion and development were halted by mass extinctions, in which many of the planet's major life forms were either entirely or partially wiped out and many others were freshly established. Such catastrophic extinction episodes are attributed to asteroids impacts, climate change, volcanic eruptions, etc. Dinosaurs were also wiped out in one such event. The largest problem the Earth is currently experiencing is climate change brought on by human activity. Although human activities may exterminate some species from the world, the planet will undoubtedly recover and return to its natural balance as it has for millions of years. However, the sun will ultimately wipe out Earth, as predicted by scientists. The Sun will lose its structural integrity and enlarge in volume as it ages and eventually runs out of the fuel that keeps it going—hydrogen—which will cause it to burn everything in its path, including life on Earth. In the end, the Sun would perish, leaving the Solar System permanently in the dark.
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