His forHelicopter
A helicopter is a type of aircraft that is lifted by one or more rotors on its top. Helicopters have another small rotor on their tail for balance and steering.
Normal airplanes get their lift from air flowing over their wings. Because helicopters get their lift from the rotating blades on their top, they don't need a runway to take off, and can just go straight up from a standing start. They can also turn around on the spot while they are in the air.
A helix is a curve in three dimensions. The thread of a screw is a helix, and wire coiled around a rod makes a helix. A spiral staircase is a helix. Some plants, like in the picture, naturally grow into helixes.
The word "coil" is sometimes used to mean a helix and sometimes used to mean a spiral, or sometimes used to mean the act of wrapping something around something else to make a helix or spiral.
In some religions such as Christianity, Hell is a place that people who have been bad during their lives are believed to go when they die.
His forHemisphere
A hemisphere is half a sphere. The word hemisphere is usually used when talking about half of the sphere of the Earth, particularly the top and bottom halves of the sphere. The top half of the Earth is called the Northern Hemisphere and the bottom half is called the Southern Hemisphere.