Answer:
Change in the vascular system.
Step-by-step explanation:
High blood pressure occurs when the arteries in the human body system become rigid thereby making the blood pressure rise.
The cause for this situation particularly in older people is the changes in the vascular system or circulatory system.
This is said to be vasoconstriction which lowers the flow of blood in the circulatory system, thereby causing high blood pressure
Hence, since Mr. Ackah is a retired teacher, it is believed that he is an old man susceptible to changes in the vascular system or vasoconstriction.