anthropocene correct answers the age of human transformation of Earth's biological and physical
systems
crust correct answers Earth's molten surface cooled and hardened into a rigid surface
cyanobacteria correct answers photosynthetic bacteria, among the earliest forms of life preserved
uniformitarianism correct answers the principle that the same gradual and nearly imperceptible
processes operating now have operated in the past, underpins almost all evolutionary, tectonic,
and erosional processes
superposition principle correct answers in a sequence of rock layers, the oldest rocks are at the
bottom, and the youngest rocks are at the top
radiometric dating correct answers assigning ages to materials based on radioactive half-life of
unstable elements in those materials
seismic wave correct answers energy released by earthquakes that travel through Earth's interior
inner core correct answers composed of solid iron and nickel, extends from Earth's center to
about 5,150 km (3,200 mi) below Earth's surface
outer core correct answers composed of liquid iron and nickel, extends to about 2,900 km (1,800
mi) below Earth's surface
lower mantle correct answers the layer of heated and slowly deforming solid rock that lies
between the base of the crust and the outer core
asthenosphere correct answers found between depths of 100 and 200 km (62 and 124 mi), softer
and weaker than the lower mantle beneath
lithosphere correct answers the crust and the lithospheric mantle beneath it, extending to a depth
of about 100 km (62 mi) on average
continental crust correct answers makes up continents, composed mainly of granite
oceanic crust correct answers beneath the oceans, composed mainly of basalt
basalt correct answers a dark, heavy, fine-grained volcanic roc
magma correct answers melted rock that is below the surface of the crust, often hardens into
granite