A person is vaccinated against pathogen P. Several years later, the concentration of antibodies against P is very low. The person then becomes infected with P.
Which statement explains why the person may still be protected?
Memory lymphocytes remain and enable rapid production of antibodies against P.
Vaccine antigens remain and directly destroy newly entering cells of P.
Antibodies change shape and enable rapid binding to any new pathogen.
Memory lymphocytes remain and release antibiotics that destroy cells of P.
45 exam-style questions on Edexcel GCSE Biology 5.3 Immune system and medicines, covering 5.3.1 The specific immune system, 5.3.2 Response to immunisation, 5.3.3 Advantages and disadvantages of immunisation, 5.3.4 Antibiotics and bacterial infections, 5.3.5 Aseptic techniques in culturing, 5.3.6 Cross-sectional areas of cultures, 5.3.7 Stages of developing new medicines, and 5.3.8 Production of monoclonal antibodies. Each one has a worked solution and a mark scheme showing where the marks go.