Chromosomes are the part of the DNA that determine traits
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.
I think stratus clouds indicate possible precipitation
Answer:
By looking at human embryo we can determine that it has a postanal tail.
Explanation:
Human embryo is a a process of life cycle that takes place after the fertilization. It takes 9 months for a human embryo to be fully developed. If we take a look at a human embryo, we will notice that it has a postanal tail.
Postanal tail is simply an extension of body. It is only during the embryonic stage that the postanal tail can be found. After the birth this feature cannot be found.
Answer:
B
Explanation:
a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one,
