Melinda sees a bear in the woods and becomes extremely scared. she decides to run away as fast as she can. when she gets home, she calms down because the bear did not follow her. in this situation, the prepared melinda's body to deal with this emergency, and the relaxed her body after the crisis.

sympathetic nervous system/parasympathetic nervous system.

Explanation:

When it comes to sympathetic nervous system, it controls our body's response to the situation that's dangerous or stressful for us.

The hormones that are secreted in our body are the main cause why our heart beats faster in these types of events, due to production of more blood which is sent to the muscles.

We start breathing faster, which means we produce more oxygen and it is further sent to the brain. Glucose is released in our bloodstream and as a result we get more energy than ever.

All these responses that are occurring in our systems are so fast that often we don't realize it at the moment of happening.

On the other hand, we have a parasympathetic nervous system.

After the stressful and dangerous event has passed, it works to calm our body down and bring back our body balance that has been lost to its normal state. Hormone levels are returned to the normal, heart rate is slowly going back to its normal state as well as blood pressure, slowly, as the body is regaining its balance.  

Sympathetic and parasympathetic work together in order to achieve the normal, healthy body function.

70 % i think is the answer.