I am thinking the rock that forms from lava that cools quickly is D) Obsidian.
I think the correct answer would be mass of the shells. According to the law of conservation of mass, mass can never be created not destroyed. Therefore, mass here should be constant before the transformation and after the process. Hope this helps.
Answer:
west to east
Explanation:
Low pressure spins counterclockwise, causing weather systems to move from west to east in the Northern Hemisphere.
