What will be the time period of simple pendulum at the center of earth

As g=0 at the centre of earth the time period becomes infinite as T=2pi/underoot g. At center of earth, r = 0 & hence g = 0. Time period of a simple pendulum is T = 2π sqrt (1/g).

Explanation:

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide