Answer: The mother of the man can be either XHXH or XHXh and pass her normal allele to the son and his father can be either XHY or XhY, he only passes his Y chromosome. The mother of the woman can be XHXH or XHXh and the father could be XhY, then she could have inherited the normal allele from the mother and the affected allele from the father. But also, the mother of the woman could be XHXh or XhXh and the father could be XHY, so in this case she could have inherited the normal alele from the father and the affected allele from the mother.
Explanation:
Hemophilia is an inherited bleeding disorder in which the blood does not clot properly. This can cause bleeding either spontaneously or after an injury.
<u>It is related to the X chromosome and it is recessive for females</u>, this mean they need both affected alleles to develop the trait. <u>Males only need one recessive allele because they only have one X chromosome</u>. This means that females need both parents to be at least carriers (although one or both can also have the disease or both recessive alleles). While males inherit it only from the mother, either she is a carrier (one recessive allele) or she has the disease (both recessive alleles). Then the mother passes the X chromosome with the affected allele to the son, and that son only receives the Y chromosome from the father, which does not have the gene that determines this disease.
If the mother is a carrier, her genotype is XHXh, being XH the normal allele and Xh the affected allele. She does not have hemophilia because she has a dominant allele. The father is XHY, so he does not have the disease because his only allele is normal (dominant)
The mother of the man can be either XHXH (she can only pass a normal allele) or XHXh and pass her normal allele to the son (in this case, the recessive allele is not inherited by chance.) His father can be either XHY or XhY, he only passes his Y chromosome which is not related to the disease. The mother of the woman can be XHXH or XHXh and the father could be XhY, then she could have inherited the normal allele from the mother and the affected allele from the father. But also, the mother of the woman could be XHXh or XhXh and the father could be XHY, so in this case she could have inherited the normal alele from the father and the affected allele from the mother.
Answer: c) and b) are correct.
The brain is encased in a protective bony or cartilaginous housing in craniates.
The anterior end of the nerve cord is elaborated to form a brain in craniates.
Explanation: The craniates include the chordata with well-defined heads. This includes mammals, reptiles and fishes. So we can discard the other answers. Because most craniates have functional jaws, and the adults do not lose their chordate characteristics. The last one does not apply as a specific feature because the tunicate have neural crest but are not recognized as craniata.
Answer:
"
Natural gas does not produce greenhouse gases as other energy sources do."
Explanation:
The answer, "Coal deposits are found on nearly every continent and mining coal poses few risks." shows only how it can be a better option, but does not show how it can benefit.
The answer, "Petroleum is relatively inexpensive compared to other forms of energy." only shows how it can be a better option, but does not show how it can benefit.
The answer, "Nuclear power increases water vapor in the atmosphere." does not clearly state how this benefits us.
<em>-kiniwih426</em>
