Question

what does the sympathetic nervous system do to the heart rate?
increases it
decreases it
causes irregular heartbeats
stabilizes it
has no effect on it

Explanation:

The sympathetic nervous system is part of the autonomic nervous system. It is activated during the "fight - or - flight" response. When activated, it releases neurotransmitters like norepinephrine which binds to receptors on the heart, increasing the heart rate to pump more blood to the muscles and organs in times of stress or danger.

Answer:

Increases it