A horse and a donkey produce an infertile mule. This shows that

  1. mules are a new species
  2. horses and donkeys are the same species
  3. only mules are mammals
  4. horses and donkeys are different species
Answer

D) horses and donkeys are different species

Members of one species produce fertile offspring. O Level Biology · Topic 2 Classification · 2.1 Concept and use of a classification system

Biology MCQ · More O Level Biology: Classification MCQs · Practise