The timing of human puberty is strongly linked to genetic and dietary factors. It is also linked to historical changes, and a secular trend favoring early menarche has resulted in an ever increasing proportion of teens attaining reproductive capacity at young ages. The causes of the trend, however, have not been unequivocally ascertained. More generally, we know very little about the factors in children's proximal environments that either inhibit or accelerate the timing of pubertal maturation. But, between 1984 and 1987, it has been distributed a survey with questionnaires to over 1,000 participants who were asked about their early family experiences and their physical development. The results from this retrospective study suggest that parental absence especially the absence of the biological father-is associated with early menarche.
Using the Hardy-Weinberg equations, the percentage of carriers of cystic fibrosis is 8.19%.
<h3>What are the Hardy-Weinberg equations?</h3>
The Hardy-Weinberg equations describe the relationship between alleles in a population that is fairly constant.
The Hardy-Weinberg equations are given below as;
Hardy-Weinberg equations
Percentage of carriers = 2pq
Percentage of carriers = 2 * 0.09 * 0.91 * 100 = 8.19%
Therefore, the percentage of carriers of cystic fibrosis is 8.19%.
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Gravitropism ensures that roots grow into the soil and that shoots grow toward sunlight. Growth of the shoot apical tip upward is called negative gravitropism, whereas growth of the roots downward is called positive gravitropism.
