What comes after sigma in the greek alphabet?

Why did thales choose water as the "primeval stuff", what us this "primeval stuff"

What is the author's purpose in this passagea. to remind people to avoid individuals who occasionally display bad manners.b. to encourage people to embrace the feeling of superiority over others.c. to persuade people to demonstrate good manners at all times.d. to convince people to freely express their emotions.

Describe a trait that would black moth survive in sooty environment explain