Ais a chemical substance used for communication that is produced at one site in the body and then carried in the blood to another

The correct answer is hormone

Explanation:

A hormone is a chemical substance produced by an organ (usually called gland) and on production is released directly into the bloodstream to be transported to another part of the body (usually called target organ) where its exert its function.

An example of hormone is thyroxine, it is produced by the thyroid gland in the neck and exert function on almost all cells of the body

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.