question_answer 34)

  Vectors can be defined as (a) animals carry the infecting agents from sick person to another healthy person (b) microorganisms which cause many diseases (c) infected person                                                         (d) diseased plants

Answer:

   (a) Vectors or intermediaries are animals insects that carry the infecting agents from a sick person to another healthy person. Mosquitoes (for malaria, filariasis, yellow fever and dengue), flies (typhoid, kala-azar, sleeping sickness), louse (typhus) and rat (for plague).