1.  1(a). Whooping cough is caused by the bacterium Bordetella pertussis, which grows
rapidly in the human body.

State the term used to describe the rapid growth of a bacterial population.                                                    (1)

(b) Children in the UK can be immunised against whooping cough.

Suggest why outbreaks of whooping cough still occur in the UK.                                                                            (2)

(c) Describe the response of the human body to immunisation.                                                                  (3)