Questions: Hypertension is a major risk factor for heart disease because it - forces the heart to pump harder, which puts more physical strain on the heart - restricts a person's salt intake, which suppresses the immune system - places stress on the thyroid system, which inflames the arteries - slows the heart rate, which leads to less efficient distribution of oxygen through the body

The answer is the first one: forces the heart to pump harder, which puts more physical strain on the heart.

Explanation for each option:

1. Forces the heart to pump harder, which puts more physical strain on the heart: This is correct. Hypertension (high blood pressure) means that the heart has to work harder to pump blood through the arteries, which can lead to heart disease over time due to the increased physical strain on the heart muscle.

2. Restricts a person's salt intake, which suppresses the immune system: This is incorrect. While reducing salt intake is often recommended for managing hypertension, it does not directly suppress the immune system.

3. Places stress on the thyroid system, which inflames the arteries: This is incorrect. Hypertension primarily affects the cardiovascular system, not the thyroid system.

4. Slows the heart rate, which leads to less efficient distribution of oxygen through the body: This is incorrect. Hypertension typically does not slow the heart rate; instead, it increases the pressure in the arteries, which can lead to other cardiovascular issues.

Summary: Hypertension is a major risk factor for heart disease because it forces the heart to pump harder, which puts more physical strain on the heart.