The secondary immune response is faster than the primary response because

  1. more macrophages are present
  2. pathogens are weaker
  3. antibodies are injected
  4. memory cells are already present
Answer

D) memory cells are already present

Memory cells divide rapidly. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

Biology MCQ · More A Level Biology: Immunity MCQs · Practise