Goods safe for environment
no.
See the related link for the symbol.
no
No.
Scroll down to related links and look at "Loudspeaker symbol and google images".
See related link.
Math
No, it was actually a Hindu symbol for strength and unity prior to WWII
I think you are referring to the Unitarian Universalist symbol. See the related link.
The recycling sign or symbol has three arrows that form a circle. I have included a related link which is an image of this symbol.
It's called the Ampersand. See the related link for more information.
It represented a symbol of darkness, which is greatly related to Hades, being the god of the underworld and its inhabitants.