Which sentence is punctuated correctly?
1. Earth's crust is divided into two types, oceanic and continental; and both are formed by the constant moving and crashing of tectonic
plates.
2. Most of Earth's crust is made up of eight elements, the largest proportion being oxygen and silicon and as such, most minerals also
contain oxygen and silicon.
3. Earth is made up of three layers, the crust, the mantle, and the core: the crust and mantle are comprised of different rocks and
minerals while the core is believed to be hot metal.
4. Although a few types of rock are composed of a single mineral, most rocks consist of a combination of more than one mineral;
indeed, the types of rock that make up the majority of Earth's crust
are all composed of several minerals.