A frog can be many different colours. It appears green under normal 'white' light because it absorbs all the other colours in the light's spectrum apart from green. It reflects the green light back and that is picked up by your eye.
If the light is red, there is no green in the spectrum of the light, only red. So, the red light will be absorbed and there is no green to be reflected back for you to see. Therefore, the frog will not look green.
Answer:
Sound waves are reflected back
So,
GPE (graviational potential energy) = mass x g x height
GPE is depends on where zero height is defined. In this situation, we define h = 0 as the initial height.



The builder has gained 18.375 kJ of PE.
Their atomic number?? (easy guess)