A6 kg rock falls from a cliff. just before it hits the ground its speed is 24 m/s. from what height did it fall?

Rock starts out at the top of the cliff with maximum potential energy = mgh
As it falls, the potential energy decreases and kinetic energy increases.
When it hits the ground, potential energy will be zero and kinetic energy will be maximum = (1/2)mv²

Do you see that the potential energy at the top of the cliff is equal to the kinetic at the bottom?

mgh = (1/2)mv²
mass cancels out
gh = (1/2)v²
gravity, g = 9.8 m/s²
velocity, v = 24 m/s
(9.8)h = (1/2)(24)²
9.8h = 288
h = 29.3877551
round to whatever place is specified for the solution.

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.