Answer: seafloor spreading and subduction magmatism
Explanation: Continental crust are termed as the crust destroyed by plate tectonic process mostly.Continental crust usually lies above sea level and because of this existence of land life to evolve from marine life possible.
Seafloor spreading is a type of process in which tectonic plate of Earth's lithosphere separate from one another. Subduction is also a process related with continental crust that occurs when tectonic plates collide with each other rather than getting apart.
Answer:
Well most transform boundaries are found on the sea floor, so I will have to say the second one.
Explanation:
Obsidian is volcanic glass compared to other igneous rocks , there’s also no proper crystallization compared to the other igneous rocks
