The most common mineral group in Earth's crust are the silicates.
They make up the largest and most important class of rock-forming minerals, and constitute around 90% of the crust of the Earth.
Answer:
Ocean Basin
Explanation:
Ocean basin, any of several vast submarine regions that collectively cover nearly three-quarters of Earth's surface. Together they contain the overwhelming majority of all water on the planet and have an average depth of almost 4 km (about 2.5 miles).
from Britannica.com
The correct answer is C. Direct democracy.
In it, the people directly vote vote on policy initiatives, unlike nowadays where representative democracy dominates.