How does the muscular system humans maintain posture?

How would you place two electrons on a sphere of radius r so that the electrostatic potential energy is minimized. how would you place three electrons to solve the same problem.

In the united states, tornadoes generally occur because of the freezing of ocean water underwater earthquakes meeting of cool and warm air masses shifting of warm and cool ocean currents

It's time for santa to deliver his presents. assuming he delivers presents all over the world, he has to travel about 75,000,000 miles. if he travels east to west, he can use the time zones to make christmas day last 31 hours. what speed, in miles per hour, must santa fly to get all of his presents delivered?