When her son fails to arrive home as expected, elena fears he has been in an accident. both her heart and respiration rate remain elevated until she sees him come safely through the door. her body soon returns to normal due to the action of her nervous system.

When her son fails to arrive home as expected, Elena fears he has been in an accident. Both her heart and respiration rate remain elevated until she sees him come safely through the door. Her body soon returns to normal due to the action of her parasympathetic nervous system.

Explanation:

Parasympathetic nervous system is part of our nervous system that helps to keep us clam and relaxed - causing homeostasis in the body. It does this by slowing down our heart beat and relaxing our muscles.

This is in start contrast to Sympathetic nervous system that controls our 'fight or flight' tendencies. It prepares our body for confrontation, increasing alertness, activeness, leading to a faster heart beat.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.

in about winter like late november to january