Anyone wanna start a convo

Light waves can move through , but they travel fastest when they move through a(n) .

What is a difference between a mixture of elements and a mixture of compounds

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium.b)heavier than helium.c)the same weight as helium.d)dependent on the element that reacted with carbon.