Answer:
a. at either A or B
Explanation:
Kinetic energy may be defined as the energy of the system or an object which is due to its velocity of the object it possess.
In the context, an object having mass is attached to spring which is vertical and the object moves up and down due to spring effect between points A and B. Now these points A and B are the extreme points after which the object bounces back.
At point A and B, the velocity of the object becomes zero and hence the kinetic energy of a body varies directly proportional to its velocity.
i.e. Kinetic energy 
Answer: Reduction in skin resistance as a result of increased perspiration leading to conduction.
Explanation:
A lie detector is a machine used to detect when someone is lying.
This is so because when an individual lies, there is an increase in heart beat which causes an increase in sweating. As the the individual sweats there is a reduction in the resistance at skin surface leading to current conduction across the connected cables.
Answer:
The evidence of water that once was on mars
Explanation:
The martian atmosphere consists mostly of carbon dioxide, but is very thin, less than 1% of Earth's atmosphere. However, the strong evidence of water on Mars in the past that our missions have found means that the atmosphere must have been thicker and warmer, or water would have evaporated away very quickly.
Evaporation is the process of water being evaporated and rising. This water vapor condenses at a certain point and mixes with aerosols to create a cloud.
