What scientific law or principle allows us to
say that all the PE is converted to KE?

The law of conservation of energy

Energy cannot be created or destroyed, but it can be changed from one form to another.

KE + PE = constant

weather forecasts are done by collecting data about the current state of the atmosphere mainly the temperature, humidity and wind and using meteorology, to determine the atmosphere that evolves over time. the h and l mean the high and low pressure. the red strip is a warm front. the blue strip is a cold front. the blue and red strip is a stationary front. the purple strip is a occluded front.

explanation:

im srry but ur wrong the answer is d a smooth rock, some red dirt, and an empty bird's nest.