I believe the first one is 'physical geography' :-)
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.
Your answer would be D) Stromatolites. hope this helps :)))!
In addition to a desire for economic profit, nationalism also served as a reason for colonization. After the French Revolution, European nations had a strong sense of national pride, and felt that in order to prove themselves as a strong world power, they would need to gain control of other countries.