Coal has had many uses over the course of history. Most recently, it is used in industrialized societies .

the median of the data is 4.

step-by-step explanation:

the median means the middle number of a given number.

to decide which one is the median, arrange in ascending or descending order. but sometimes, you may find two(2) number in the middle, but it's easy, just add them together and divide by 2.

so,   determine the median of the data. 2, 3, 3, 4, 5, 7, 9

it is already arranged, count 3 times forward and 3 backward and the one left is your answer.

2,3,3,4,5,7,9

our answer is 4.

hope this !

the branch of biology that deals with the normal functions of living organisms and their parts.

the way in which a living organism or bodily part functions.

answer; conditional stimulus will trigger a conditioned response;

answer; exploratory;