Solution:
The layer below the Earth's crust is known as outer mantle. This consists of magma.

Solution:
Salt in the ocean comes from rocks on land. The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid (which forms from carbon dioxide and water).

Solution:
both (a) and (b)

Solution:
The longest epoch of the tertiary period is Eocene.

Solution:
The R-horizon of soil horizon consists of unweathered bedrock.

Solution:
The strongest bonds exist between the particles found within igneous rocks.

Solution:
The Archaean Rock system.