The theory of evolution is a shortened form of the term “theory of evolution by natural selection,” which was proposed by Charles Darwin and Alfred Russel Wallace in the nineteenth century
Answer:
The correct answer is A. autosomal recessive
Explanation:
In an autosomal disease, the mutation occurs in the autosomal chromosome, not in the sex chromosome. In autosomal recessive disease if both the defected allele from parent comes in the child then only the child would be affected by the disease. If the offspring have single defected allele than he is said to be a carrier.
So as the defect is not in sex chromosome the disease will occur in the same frequency in both the sexes and if parents are carriers which means they are not affected by disease than 25% offspring can have the disease because out of four offspring one can get both the defected allele, one from each parent. So the correct answer is A.
D is the correct answer i think.
Answer:
2 cells meet and the number of chromosomes becomes equivalent to the somatic cell.
Explanation:
In meiosis crossing over occurs and the number of chromosomes divided or remain half as compared to a somatic cell which is called Haploid (n). When two haploid cell meets than diploid (2n) cell formed which further transforms into a zygote. So, the purpose of meiosis is the cross over which creates genetic variation among individuals and reduced the number of chromosomes into the half. Because if the number of chromosomes remains the same as (2n) and (2n) meets and becomes 4n. Which is the wrong pattern so nature keeps this balance in a unique manner that (n) and (n) meets and form (2n).
