The answer here is D, and it's kind of obvious. But you probably already knew the answer and are just doing this for piece of mind.
Explanation: Just the fact that we don't know whether or not there even is extraterrestrial life rules out every other answer, without even needing to go in depth.
(Okay, I read your question completely wrong, it's asking for which one of these has been solved isn't it?)
This is tough because all of these other than D have been figured out. Go with the methane atmosphere then.
The sponge-like structure, as well as the high salt content of water and the <span>ease of contaminating water contribute to the environmental stress on a coral reef.
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Binary fission is a form of asexual reproduction used by members of domains archaea and bacteria among other organisms. Like mitosis (in eukaryotic cells), it results in cell division of the original cell to produce two viable cells that can repeat the process. Hope I’ve helped ;)
Answer:
how ever fast the wind is
Explanation: