What is the primary source of electrical power for most long-term orbiting operational satellites?

In the context of Indian satellite launch vehicles, what does 'G' stand for in GSLV?

Which type of satellite orbit is most commonly used for continuous weather monitoring and forecasting over a specific region?

Which of the following statements is/are correct regarding Medium Earth Orbit (MEO)? I. Satellites in MEO do not follow specific predictable orbits around Earth. II. MEO is very commonly used by navigation satellite systems like GPS and GLONASS.