Every few years, Shelley takes her dog in for injection with a rabies vaccine, which contains the heat-killed virus. Is the dog receiving active or passive immunity from the injection? Explain.

Passive immunity

Explanation:

Active immunity occurs when the immune system of an individual encounters a disease and produces antibodies to fight against it. This type of immunity is usually slow but when achieved the effect lasts for a lifetime.

Passive immunity involves the introduction of antibodies into the body of individuals. The effect is usually instant but it lasts for a short period of time. This explains why every few years, Shelley took her dog in for injection with a rabies vaccine which contained the heat-killed virus.

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.