12 May 2023 Static Quiz

Correct Answer: B
Explanation
Composite Volcanoes: These volcanoes are characterised by eruptions of cooler and more viscous lavas
than basalt. These volcanoes often result in explosive eruptions. Along with lava, large quantities of
pyroclastic material and ashes find their way to the ground. This material accumulates in the vicinity of
the vent openings leading to formation of layers, and this makes the mounts appear as composite
volcanoes.

Correct Answer: C
Explanation
Crust: This is the outside layer of the earth and is made of solid rock, mostly basalt and granite. It is
brittle in nature. There are two types of crust; oceanic and continental. Oceanic crust is denser and
thinner and mainly composed of basalt. Continental crust is less dense, thicker, and mainly composed of
granite. Statement 1 is Incorrect while Statement 2 is correct. The mean thickness of oceanic crust is 5
km whereas that of the continental is around 30 km. The continental crust is thicker in the areas of
major mountain systems. It is as much as 70 km thick in the Himalayan region. The crust is separated
from the mantle by Moho discontinuity. Statement 3 is Incorrect.

Correct Answer: C
Explanation
There are several factors affects decomposition of organic matter. They are Moisture ,Sufficient Oxygen
Warm temperature,PH of the soil, Composition of the matter .

Correct Answer: B
Explanation
Fold mountains: These are created where two or more of Earth’s tectonic plates are pushed together.
Statement 1 is correct. At these colliding, compressing boundaries, rocks and debris are warped and
folded into rocky outcrops, hills, mountains, and entire mountain ranges. Most fold mountains are found
on the edge or former edge of continental plate boundaries Some of the fold mountains are the
Himalaya, the Alps, the Rockies etc. Aravali once was a fold mountain. It is one of oldest fold mountain
in the world which is now left in residual form. Statement 3 is correct.
Block Mountains: Block mountains are formed due to upward movement of the middle block between
two normal faults . The up-thrown block is also called horst. Block mountains may be formed when the
side blocks of two faults move downward whereas the middle block remains stable at its place. Block
mountains may be formed when the middle block between two normal faults moves downward. Thus,
the side blocks become horsts and block mountains.
Ex- Great African Rift valley and Rhine Valley (graben) and Vosges mountain (horst) in Europe.
Statement 2 is Incorrect.

Correct Answer: A
Explanation
Earth Flow: The flow of water-saturated clayey or silty materials down low-angle terraces or hillsides is
known as earthflow.
Mud Flow: In the inadequacy of vegetation cover and by massive rainfall, thick layers of weathered
matter get soaked with water and both slowly or rapidly flow down by certain channels.
Rapid Movements: Rapid movements are most common in humid climatic regions and happen over
gentle to steep hills/slopes.
Solifluction: It includes gradual and slow, downslope flowing soil mass or fine-grained rock debris
immersed or lubricated with water.