If it's properly adjusted ur head and nexk will stay in place for no further injuries.It helps so it don't move
The correct answer among the choices given is the last option. Galaxies are classified according to their shapes or visual morphology. There three main types of galaxies currently. They are the elliptical, spiral and irregular. Elliptical galaxies are like a spheriod or an elongated sphere. Spiral galaxies are characterized and distinguished by having a bulge, a disk and a halo. Lastly, irregular galaxies do not have regular or symmetrical shape.
Answer:
it can occur between hydrogen and 3 other elements
Explanation:
These elements are:
Nitrogen
Oxygen
Flourine