Answer:bromine
Explanation: because im smart and i did this already so i know the answer so your welcome :D
Answer: They are responsible for animal migration because the chemicals they contain cause the animals to move to a different environment.
Explanation:
I found this information from https://jeb.biologists.org/content/222/Suppl_1/jeb191890
They build up in the thylakoid, where they bond to each other to create ATP.
Not 100% about this but that's what i got.