For mendel to have postulated the law of independent assortment which of the following reasons had to be valid?
a) all the traits that mendel examined involved genes that did not display genetic linkage.
b) several of the phenotypes that mendel examined involved color.
c) mendel observed chromosomal segregation in pea-plant cells.
d) mendel carried out his experiments on plants and not on fungi.
e) none of the above

Option (A).

Explanation:

Mendel is known as the father of genetics. He explains the concept of dominance and introduces the law of segregation and law of independent assortment.

The law of independent assortment explains that the segregation of one pair of character is independent on the other character. The law of independent assortment is valid because the trait used by the Mendel are located on different chromosome and does not show the linkage.

Thus, the correct answer is option (A).

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.