BI-351
Observed and expected ratios
Biology · Secondary 3 · Medium · Observed and expected ratios
In a cross between two heterozygous pea plants for seed shape, the expected ratio of round : wrinkled seeds is 3 : 1. A student grows 16 seeds and counts 11 round and 5 wrinkled. Which is the best reason for this difference from the expected ratio?
- The sample size is small, so random chance affects the ratio more strongly.
- Round seeds suddenly became recessive in this generation.
- All the wrinkled seeds mutated into round seeds after fertilisation.
- The 3 : 1 ratio only applies if exactly 16 seeds are produced.
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