A family of five daughters is expecting the sixth issue. The chance of it beings a son is :
Correct answer: C. 50%
- A. 0%
- B. 25%
- C. 50%
- D. 100%
Explanation
In humans, sex determination is governed by the X and Y chromosomes. A female (XX) can only provide an X chromosome, while a male (XY) can provide either an X or a Y chromosome. The combination of these chromosomes during fertilization determines the sex of the offspring: XX results in a female, and XY results in a male. Each pregnancy is an independent event with a 50% chance of resulting in either sex. The existence of previous children of a specific sex does not influence the probability for the next child. Therefore, the chance of the sixth child being a son is 50%. The other options suggesting 0%, 25%, or 100% are incorrect because they do not reflect the equal probability of each sex determined by genetic principles.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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