Q4. Assertion: coronary artery disease can cause angina. Reason: deposits in the coronary arteries narrow their lumen, so less oxygen reaches the heart muscle. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion: the deposits make the lumen narrower (NCERT page 203), and angina appears when not enough oxygen reaches the heart muscle (page 203).
Q5. Name the four substances whose deposits narrow the arteries in coronary artery disease.
Calcium, fat, cholesterol and fibrous tissues (NCERT page 203).
Q6. Name two vital organs that high blood pressure affects, besides the heart.
The brain and the kidney (NCERT page 203).