The microscopic observations of cells form the basis of the cell theory and the idea that all living things are composed of cells; cells are the structural and functional unit of living things.
Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate. Such factors as stress, caffeine, and excitement may temporarily accelerate your heart rate, while meditating or taking slow, deep breaths may help to slow your heart rate.
The toxins would enter through the Xylem.
Answer:
Option C
Explanation:
Option
A. 6440 mL/min
B. 4340 mL
C. 3500 mL/min
D. 2940 mL/min
Solution
It is required to find the minute ventilation which is equal to the product of rate of breathing and the total amount of gas being inhaled or exhaled per breathe. Let this minute ventilation be denoted by "
"
Thus,

where TD is the tidal volume and Br is the rate of breathing
Substituting the given values we get

We will now reduce the air held in the conducting zone of respiratory system
Air held per breathe 
Total Air held

Amount of fresh air one can breathe in and out every minute

Hence, Option C is correct