Answer: B. beta
Explanation:
Sickle cell anemia is a inherited disorder which occur due to mutation of gene responsible for synthesis of hemoglobin protein. Typically the gene which is responsible for synthesis of beta-globin protein which make the beta chains in the hemoglobin is affected by the mutation. As a result of this the red blood cells acquire a shape of sickle rather than round. Pain, cold, stress, dehydration and illness are the symptoms associated with this disorder.
Frequent inbreeding within a species can result in extinction of the species. The recurring set of available genes during reproduction allows for decreased genetic diversity.
There are choices for this question namely:
Carvedilol
Betaxolol
Acebutolol
Propranolol
Metoprolol
The correct answers are "betaxolol", "acebutolol",and "metoprolol". These drugs are from the class called beta blockers as they inhibition the action of beta receptors in the heart leading to a decrease in heart rate and blood pressure. There are also beta receptors in the bronchial tree, an inhibition of which will lead to bronchoconstriction.
Betaxolol, acebutolol, and metoprolol are cardioselective beta blockers and only blocks the beta receptors located in the heart. Carvedilol and propranolol are non-selective beta blockers that can cause bronchoconstriction which is contraindicated in patients with asthma.