16.It is essential in order for us to see things around us.

A. Light

B. Radiation

C. Luminous

D. Reflection

17. It allows all light to pass through it.

A. Opaque

B. Transparent

C. Translucent

D. none of the above

18. Back and forth movement of the sound..

A. Vibration

B. Light

C. Sound

D. Echo

19. It blocks the light..

A. Opaque

B. Transparent

C. Translucent

D. Light

20. Energy at rest or stored energy.

A. Kinetic Energy

B. Potential Energy

C. Mechanical Energy

answer my question please. :).​