Balance in the water cycle means that

a)the average annual precipitation over earth equals the amount of water that evaporates
b)water that falls to earth only enters oceans<
c)the amount of water that falls to earth weighs the same as the amount that condenses in clouds
d)water that evaporates from earth's surface remains forever in the atmosphere

i think it is a but i'm not sure.

Amass attached to a spring is displaced from its equilibrium position by 5cm and released. the system then oscillates in simple harmonic motion with a period of 1s. if that same mass–spring system is displaced from equilibrium by 10cm instead, what will its period be in this case? a mass attached to a spring is displaced from its equilibrium position by and released. the system then oscillates in simple harmonic motion with a period of . if that same mass–spring system is displaced from equilibrium by instead, what will its period be in this case? a) 0.5sb) 2sc) 1sd) 1.4s