Evidence of a chemical change can be observed when- A. a solid melts into a liquid.
B. cookies are crumbled.
C. a drink is poured from a can to a cup.
D. a banana turns brown after being cut.

A. a solid melts into a liquid

Explanation:

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.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.