Explian the construction of electric motor?

In a stagnant pool of water, a crayfish may spend much of its time lying with one side of its carapace near the surface of the water. in this position, it will move the walking legs on that side in a rhythmic back-and-forth motion. explain the likely function of this behavior.

Which one of the following research methods can show cause and effect

The pressure proportional to the area a- inversely b- directly c- increase d-decrease