I think the answer is <span>C. trial-and-error learning</span>
Igneous rock derives it's name from the Latin word ignis which means fire. It is formed when the magma after volcanic eruption gets cool and solidified either on the surface of earth crust or inside the earth crust. These rocks are characterized by their hardness. These rocks undergoes no chemical weathering but exhibit very low mechanical or physical weathering may occur. Therefore, hardness is the property which can be used to identify the origin of an igneous rock.
Answer:
Greenhouse affect - atmosphere traps heat
Ice age - coldest phase of climate cycle
Sun's output - can vary
Greenhouse gases - atmosphere traps even more heat
Answer:
In a federal system there is no centralized authority, while in a confederal system power is distributed equally among the states.
Explanation:
The Federal government is a type of government in which sovereign power rests with the central government, while in a confederal government political power rests with individual states and very little with the central government.