Why got white theme and black theme at settings, what are those used for?

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

For waves in the ocean, the medium of the waves is a. air b. water c. energy d. a passing boat

Chameleons catch insects with their tongues, which they can rapidly extend to great lengths. in a typical strike, the chameleon's tongue accelerates at a remarkable 220 m/s2 for 20 ms, then travels at constant speed for another 30 ms.