A sphere has one point of symmetry (at its very center) if one considers rotational symmetry in its three dimensions. If one is only considering reflectional symmetry, it would have an infinite number of lines of symmetry.
To describe a shape's rotational symmetries, you would write the angle. For example, let's use a square. If you rotate a square 90 degrees, it will look exactly the same, and 180 will be the same too, so a square's rotational symmetries are 90 and 180 degrees.
A sphere is as symetrical as any shape can get. It has an infinite amount of lines of symetry if that line goes through the center
There are various characteristics and attributes that would describe a sphere. A sphere is a perfectly symmetrically round or circular three dimensional object.
a sphere or 3D circle
By saying: It is a red sphere.
A sphere would fit the given description
A circle or a sphere would seem to fit the given conditions
No, the center of mass of a body is a point where the entire mass of the body can be considered to be concentrated. If there is no mass at a point, the center of mass cannot exist at that point.
Technically you can not trace a sphere. If the base conditions are the same as for the other solid shapes, for example a cylinder, there is a base on which the cylinder rests, which creates the circle when it is traced. A sphere on a base would be touching in one point, which would be a dot. If you trace half a sphere, yes, than you do get a circle.
the gradient of a graph at any point.
It's the middle point of line. Hardly! How far would that be from a point 3/4 way along the line? Try centre of a circle, or of a sphere.
The focal point is in front of the retina