2. Which of the following best describes significant digits? (A) Helps with estimation
(B) Indicates the precision of a measurement
(C) It is an exact number
(D) Used for counting of numbers

It is an exact number

explanation:

as the height from which the ruler was dropped increased, the speed of the ruler at ryan's hand increased.

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer