The work done by the elephant to lift one log is the force multiplied by the height at which the log has been lifted:

And so, the total work done to lift the 7 logs is 7 times the work done to lift each log:
Interference and diffraction are the phenomena that support only the wave theory of light. Options 2 and 3 are correct.
<h3 /><h3>What is the interference of waves?</h3>
The result of two or more wave trains flowing in opposite directions on a crossing or coinciding pathways. This phenomenon is known as the interference of waves.
The phenomenon of interference occurs when two wave pulses are traveling along a string toward each other.
The light wave hypothesis states that light behaves like a wave. Since light is an electromagnetic wave, it may be transmitted without a physical medium.
Light has magnetic and electric fields, much like electromagnetic waves do.
Transverse waves, such as those seen in light waves, oscillate in the same direction as the wave's path. A wave of light may experience interference as well as diffraction as a result of these properties.
All of the remaining options are the light phenomenon.
Hence, options 2 and 3 are correct.
To learn more about the interference of waves refer to the link;
brainly.com/question/16098226
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