The correct answer is: B. Males and expressed by males
Haemophilia is a hereditary disease that affects the blood’s ability to clot. It is caused by a deficiency of one of the proteins that are necessary for blood clotting. Haemophilia is usually inherited from a person’s mother, but it is expressed in males. This is because the gene for haemophilia is located on the X chromosome, and males only have one X chromosome. If a male inherits the gene for haemophilia from his mother, he will have the disease. Females, on the other hand, have two X chromosomes. If they inherit the gene for haemophilia from their mother, they will be carriers of the disease, but they will not usually have the disease themselves.
Haemophilia can cause a variety of symptoms, including bleeding into the joints, muscles, and other tissues. In severe cases, haemophilia can be life-threatening. There is no cure for haemophilia, but there are treatments that can help to control the bleeding and prevent complications.
The following are brief explanations of each option:
- A. Females and expressed by males
This option is incorrect because haemophilia is usually expressed in males.
- B. Males and expressed by males
This option is correct because haemophilia is usually inherited from a person’s mother, but it is expressed in males.
- C. Females and expressed by females
This option is incorrect because haemophilia is usually expressed in males.
- D. Males and expressed by females
This option is incorrect because haemophilia is usually expressed in males.