What cause people to fear darkness?

The unseen and unknown.

Human brain is wired for certainty. Darkness is non existence of light, hence absence of eye sight. Without vision our brain goes into a primal state. Our senses cripple as we shift into flight or fight mode. Amygdala, part of the brain responsible for emotional reactions, signals the autonomic nervous system into overdrive as our heart pumps faster, sweat glands secrete and we experience adrenaline surge in the face of impending danger. An unknown and unseen danger even though it is non existent and irrational.

Why aren't there 10 days in a week?

Your question: Why aren't there 10 days in a week?Days are determined by a precise astronomical cycle, the rotation of the earth on its own axis.Years are determined by another precise astronomical cycle, the revolution of the earth around the sun.Months are approximately based on an astronomical cycle, the revolution of the

What type of cardio is doable if one has bad knees, other than swimming?

Cycling can be adjusted to be kind to knees if you have at least 125 degrees of knee flexion/bend. Saddle height and set back can be adjusted to be kind to knees as can gear selection. Using a small hill climbing gear on flat terrain will reduce the pressure on the knees while still

How are personal trainers using social media?

In a world that is all about technology, personal trainers should use social media to promote themselves/business.Snapchat for exaplme has over 158 million daily active users, so this is a great app for PT to use.Personal trainers can utilize social media toShow potential clients what training with them will consists ofChat on