The answer is a. endothermic.
In endothermic reaction, as the name suggests, the reactants require energy absorption to form and complete the chemical reaction to form products.
And even if you don't know the answer, you can exclude all other answers by scientific logic and you will be left with the correct answer.
Hope this helps.
Answer:
Explanation:
The attached figure shows the whole description. Considering the applied force is 100 N.
The acceleration of both blocks A and B, 
Firstly calculating the mass m using the second law of motion as :
F = ma
m is the mass
m = 125 kg
It suddenly encounters a surface that supplies 25.0 N a friction, F' = 25 N
So, the new acceleration of the block is 
. Hence, this is the required solution.
The blank answer is lines of force
C. Molecules in the original disturbance disturb (move) adjacent molecules which disturb more adjacent molecules and so the wave travels.
<h3>What is wave?</h3>
A wave can be defined as a propagating dynamic disturbance of one or more quantities.
A wave can be propagated in longitudinal or transverse method.
When waves start as a disturbance (an input of energy) in a medium (water, air, the earth etc).
The energy of the disturbance is moved from the starting point to other places in the medium by molecules in the original disturbance disturb (move) adjacent molecules which disturb more adjacent molecules and so the wave travels.
Thus, the correct option is C.
"Molecules in the original disturbance disturb (move) adjacent molecules which disturb more adjacent molecules and so the wave travels".
Learn more about waves here: brainly.com/question/25847009
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