Answer:
B.The force of friction between the block and surface will decrease.
Explanation:
The force of friction is given by
where 
is the coefficient of friction and 
is the normal force.
When the student pulls on the block with force 
at an angle 
, the normal force on the block becomes
and hence the frictional force becomes
.
Now, as we increase , 
increases which as a result decreases the normal force 
, which also means the frictional force decreases; Hence choice B stands true.
<em>P.S: Choice D is tempting but incorrect since the weight </em>
<em> is independent of the external forces on the block. </em>
Answer:
c.an extinct oceanic hot-spot volcano that has subsided below sea level
Explanation:
- Marine geology defines a guyot as an isolated underwater volcanic mountain with a flat top more than 200m below the surface of the sea.
-The flat top is due to years of wave erosion.
-Guyots can form a chain of seamounts as the ocean plate of the Earth's crust moves slowly over a hot spot that remains stationary beneath the plate.
The answer is B. build up of plant materials. This is because those rocks that are composed of materials, which are organic matters from decaying plants, formed by biological activity are called biogenic or organic or non-clastic rocks. On the other hand, clastic rocks are made up of gravel, sand, silt, and clay.
Jupiter i hope it is right answer
