The correct answer is:
D. Extrusive rocks.
The explanation:
when extrusive igneous rocks form when magma reaches the Earth's surface a volcano and cools quickly. Most extrusive (volcanic) rocks have small crystals. Examples include basalt, rhyolite, andesite, and obsidian.
Ek = 6KJ.
In physics, the kinetic energy of a body or object is the one that owns due to its movement and is given by the equation
, where m is the mass of the object in kilograms and v is the velocity in m/s.
An object that it has a mass of 30 kilograms and moves with a velocity of 20m/s, its kinetic energy is given by:

Use energy conservation to calculate the speed!
Total kinetic energy before collision = total kinetic energy after the collision.
Answer:
length of column is 140.42 m
Explanation:
in 1 min the soldiers travels 114 steps
so to complete 1 step the time taken by the soldiers =
t = 
t =
t = 0.526 s
speed of sound = 343 m/s
length of the column = v × t
= 343 m/s × 0.526 s
= 140.42 m
hence the length of column is 140.42 m
C. Specific gravity is the answer