To free the rock from atop the perch, you need a , which could take the form of a person or a lever to free the rock. a. workb. photonsc. kineticd. catalyste. potentialf. electromagnetic energyg. heat

Option (D)

Explanation:

In terms of chemistry, a catalyst is usually defined as the substance that is commonly used in a reaction in order to increase the rate of reaction, without getting consumed. It helps in the reduction of activation energy.

In the given case, the lever or a person can be considered as a catalyst because both of these will increase the efficiency (or rate) in removing the rock from the top of the perch. Thus, the lever or the human will remain the same after the removal of rock as a catalyst can be recovered after the reaction.

Therefore, the correct answer is option (D).

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imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.