Questions

Jupiter has 67 natural satellites. Eight of Jupiter's moons are regular satellites, with 4 large, spherical moons, and 4 smaller moons that orbit closer to Jupiter. Jupiter has an additional 55 tiny irregular satellites.

The planet with the second highest number of moons is Saturn, with 61 moons.

Earth has only one natural satellite i.e, Moon.

Mercury and Venus have no satellites.

Magnesium is dissolved in seawater at a concentration of about 1,000 parts per million and is the only metal directly extracted from seawater.

RADAR - RAdio Detection And Ranging.

A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. 

Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.

Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed.