Expected ratios in a cross are often not seen exactly because

  1. fertilisation is random and numbers are small
  2. mutations always happen
  3. the parents are always homozygous
  4. genes change during the cross
Answer

A) fertilisation is random and numbers are small

Chance matters with small samples. O Level Biology · Topic 17 Inheritance · 17.3 Inheritance

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