A 6 cm object is 8 cm from a convex lens that has a focal
length of 2.7 cm. The image is 4 cm from the lens.

Magma  is composed of molten rock and is  stored  in the earth's crust. lava is  magma  that reaches the surface of our planet through a volcano vent.

Answershe should not have multiplied the sulfur atoms by the subscript 4

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.