Hydrogen is by far the most abundant element in the universe. It makes up about 93 percent of all atoms in the universe and about three-quarters of the total mass of the universe. Hydrogen occurs both within stars and in the interstellar space (the space between stars).
It is an imaginary line from the Earth's north pole to its south pole, passing through the center of the Earth. Imaginary in the sense that it is not marked in any way; howeve â¦ r, Earth rotates around this axis.
Definition of X-Axis. The coordinate plane is formed by the intersection of two number lines, a horizontal number line and a vertical number line. The horizontal number line is called the x-axis. The equation of x-axis is y = 0. The y-coordinate or ordinate of every point on x-axis is equal to 0. The figure shows the coordinate plane formed by the intersection of the x- and y- axes. Their point of intersection is called the origin.