What is permittivity​

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

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.

What tightening torque should be used for a hexagonal head screw (not split-bolt) on a 250 kcmil conductor?