Resting heart rate is
a)
heart rate after completing a period of exercise.
b)
desirable minimum heartbeats needed to reach a level of activity and maintain that heart rate necessary to improve your cardiovascular fitness.
c)
number of contractions of the heart that occur in a one minute when your body is at rest.
d)
the minimum number of beats per minute your heart must beat to be able to fall asleep.

Resting Heart Rate is:

c)
Number of contractions of the heart that occur in a one minute when your body is at rest.

Smoking damages the respiratory system by inhalation of a foreign substance, that is absorbed and residue is left behind on our lungs sponge like substance. the gas that is inhaled also increase your blood pressure and dilates your blood vessels. also the process of inhaling and exhaling the smoke it causes irritation to the throat and mouth. smoking can cause lung cancer and other respiratory and circulatory diseases.