One of the advantages of outbreeding is

1. Analyze the question It asks for an advantage of outbreeding. Outbreeding means mating between unrelated individuals, such as different varieties, breeds, or strains of the same species. It is the opposite of inbreeding, which is mating between closely related individuals.

2. Explain the concept Outbreeding increases heterozygosity, meaning more genetic variation in the offspring. This produces hybrid vigour (heterosis). Its main benefits are:

• Greater genetic variation in the population
• Reduced expression of harmful recessive genes, because these are masked by dominant alleles
• Improved resistance to diseases
• Better adaptability and survival
• Sometimes better yield and fertility

Inbreeding does the opposite. It increases homozygosity, exposes harmful recessive genes, and makes organisms more prone to disease and weakness.

3. Work through the options

• A. Pests tolerance: This is a specific trait, not the general benefit of outbreeding. It could be bred in, but it is not the standard textbook answer.
• B. Disease resistance: Genetic variation and heterozygosity give offspring stronger immunity and fewer inherited weaknesses. This is the classic stated advantage.
• C. Fast growth: Hybrid vigour can improve growth, but growth rate is not the standard listed advantage and depends on the specific cross.
• D. Tall height: This is a particular trait, not a general advantage of outbreeding.

4. Answer The best choice is B. Disease resistance.

5. Exam tip Link the words to their effects:

• Outbreeding → variation → vigour → disease resistance
• Inbreeding → uniformity → harmful recessives show → weakness

When a JAMB question asks for the advantage of outbreeding, look for "hybrid vigour", "resistance to disease", or "variation".