Which phrase best describes the path of a light wave? A. Parallel to the source
B. Perpendicular to the source
C. Spiraling around the source
D. Straight away from the source

D

Explanation:

Light waves travel in straight paths called rays. Unlike sound, where waves have to travel through matter to be heard, light waves do not have to travel through matter to be seen. Instead, rays travel in a straight path until they hit an object. A ray's straight path is the path of light

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

c. 75.7

i think that is the right