D. is a recent development resulting from the burning fossil fuels
the autonomic (involuntary) nervous system controls the rate at which the heartbeats. sympathetic (fight or flight) signals speed up the heart’s rate while parasympathetic (rest and digest) signals slow it down. The part or parts of the heart that forms sympathetic and parasympathetic neurons form synapses is called cardiac plexus.
Cardiac plexus is a plexus of the nerves that are present at the base of the heart and is divided into superficial and deep part. The sympathetic and the parasympathetic nerves form synapses with heart in the form of cardiac plexus.
The sympathetic nerves are responsible for activating flight or fight mode while parasympathetic nerves are responsible for restoring the normal body state.
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B is correct
D is appealing but the electrons spend more time around the oxygen than the hydrogen
