Answer:
Obviously Lengthen...
or 
Explanation:
As we can observe from the equation, time period of a simple pendulum depends upon the length directly. When the gravitational acceleration increases the time period of the pendulum decreases and vice versa. So, by increasing the length, the time period can be adjusted...
An ampere (AM-pir), or amp
I think it would be d because development in nations needs more population
While ice melts, it remains at 0 °C, and the liquid water that is formed with the latent heat of fusion is also at 0 °C. The heat of fusion for water at 0 °C is approximately 334 joules per gram, and the heat of vaporization at 100 °C is about 2,230 joules per gram. So it will be C