Answer:
They fall from the clouds as ice crystals.
They form around particles in the atmosphere.
They form when water vapor is converted directly to ice crystals.
Explanation:
It's C, the catalyst remains unchanged through a reaction.
Different codons can produce the same amino acid due to the way they bind to transfer RNA (tRNA).
I believe that they’re norepinephrine (NE), and the acetylcholine (Ach). Hope this helps!