On the em spectrum, visible light is found between question 10 options: ultraviolet rays and gamma rays. television waves and infrared rays. radar waves and x-rays. infrared rays and ultraviolet rays.

Visible light is found between infrared rays (lower frequency, higher wavelength) and ultraviolet rays (higher frequency, lower wavelength). This the spectrum of light that we are able to see reflected back at us, and is also the spectrum of color that we are able to see. 

Answer is D

Some type of thing that was invisible

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.