A microbiologist is growing bacteria cultures in the lab. After 5 minutes, a bacteria colony has 1.3 million organisms. After 12 minutes, the same colony has 41.5 million organisms. After 15 minutes, the
colony has grown to 101.3 million organisms. Is this a proportional or non-proportional relationship?
A Proportional; the constant of proportionality is 6.8 million organisms/minute
B Proportional; the constant of proportionality is 3.5 million organisms/minute
C Non-proportional; the rate of change is 19.9 million organisms/minute
D Non-proportional; there is no constant rate of change