More malaria cases are now being recorded in Europe. Other diseases, once limited to tropical countries and spread in the same manner as malaria, have also reached parts of Europe. Tropical countries have a higher mean temperature and humidity than Europe. What could account for the rise in the number of cases of these diseases in Europe?
- A1, 2 and 3
- B1 and 2 only
- C1 and 3 only
- D2 and 3 only