WAEC Biology 2018 Theory — Question 13
Question 13 of 19 from the West African Examinations Council (WAEC) Biology 2018 Theory paper, with the correct answer and a full explanation.
Advertisement
4.(b) Two heterozygous yellow flowers are crossed. Using a genetic diagram, state the phenotypic and genotypic ratios of the first filial generation.
Model answer
Cross: Yy × Yy → offspring YY, Yy, Yy, yy. Genotypic ratio = 1 YY : 2 Yy : 1 yy. Phenotypic ratio = 3 yellow : 1 (non-yellow), since Y (yellow) is dominant over y.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.