Answer:
This disorder is caused by a recessive allele, its inheritance is sex-linked.
Explanation:
The disorder affects boys born to unaffected parents, this means that at least one of them has to be a carrier of the allele which causes the disease. So, if the allele was dominant, it would express in parents and sons. But, in this case, only is expressed in sons, so it can´t be dominant. Moreover, this condition has a sex-linked inheritance because it is always seen in boys and never in girls. This happens due to boys only have an X chromosome, so if they inherit the recessive allele of the disease, they will express it. On the other hand, girls have two X chromosomes, so if they inherit one copy of the recessive allele, they will be carriers and they won't be affected.
This disorder is never seen in females because they need to have two copies of the recessive allele. However, to have double copy, they should inherit one copy from their mothers and one copy of their fathers, but boys with the allele are affected and they die in early teens without having progeny. Therefore, a girl can't have a "carrier-father", so they will never have two copies to express the disorder.
Answer:
The correct answer will be option-C
Explanation:
Comparative anatomy is the branch of study which studies anatomy or skeletal structure of the different species and comparing them to study the relationship between them.
The comparative anatomy is studied to study the evolutionary relationship between the different species which acts as evidence of the evolution. The study has distinguished the skeletal structure as homologous structures or analogous structure.
The correct answer will be option-C.
Answer:
antibodies to a disease bacterium
Explanation:
The correct answer is sex linkage.
Sex linkage refers to the phenotypic expression of an allele, which relies upon the gender of an individual and is directly associated with the sex chromosomes. These genes are regarded sex-linked as their expression and patterns of inheritance vary between the males and females. The sex linkage cannot be the same as genetic linkage, the sex-linked genes can be associated genetically.
