Pollution cleanup efforts A. are usually more expensive than preventing the pollution in the first place B. are very difficult once pollutants are dispersed into the environment
C. are often required because of inefficient resource management in factories that have not found ways to reduce, recycle or reuse hazardous materials used in production
D. are usually the result of public pressure on polluters
E. all of these answers​

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 !

i honestly have no idea

answer; role- taking;