Correct Option
The correct option is (c).
Explanation
Breathing rate is defined as the number of times a person breathes in and out in a minute. This rate varies according to the body's oxygen requirement, which changes based on physical activity levels.
Statement-wise Analysis
- Statement 1 is Incorrect. On average, an adult human being at rest breathes in and out 15–18 times per minute. A rate of 40–50 times per minute is significantly higher than the normal resting range.
- Statement 2 is Correct. During heavy exercise, the body requires more energy, leading to a faster breakdown of food. To supply the necessary oxygen, the breathing rate increases. Standard texts indicate that during heavy exercise, the breathing rate can increase up to 25 times per minute.
- Statement 3 is Correct. While exercising, merely increasing the rate of breathing is often insufficient. Consequently, deep breaths are taken to maximize the volume of air inhaled, thereby supplying more oxygen to the cells to speed up the breakdown of food for energy release.
Key Takeaway: The normal breathing rate for a resting adult is 15–18 times per minute, whereas during heavy physical activity, it increases significantly (up to 25 times per minute) and involves deeper inhalations to meet oxygen demands.