The normal breathing rate of a healthy adult human is about 16 to 20 breaths per minute. This rate can vary depending on age, health, and activity level. When you are resting, your body takes around 16 to 20 breaths in one minute to bring oxygen into the lungs and remove carbon dioxide.

Breathing is an important process that helps the body get the oxygen it needs to function and get rid of waste gases. If the breathing rate is too fast or too slow, it can be a sign of health problems.

The other options are incorrect:
- 15-11 breaths per minute is a bit low.
- 25-26 and 32-35 breaths per minute are higher than normal resting rates and usually happen during exercise or illness.

So, the correct answer is 16-20 breaths per minute.