The universal trigger for fear is the threat of harm, real or imagined. This threat can be for our physical, emotional or psychological well-being. While there are certain things that trigger fear in most of us, we can learn to become afraid of nearly anything.
D. The percentage of muscle and body fat is often defined as the mass of the body which is why this is taken into account when measuring the BMI for children and teens. It might not use all of the fat, but some parts of it is needed to measure the mass effectively.
They are all located in the dermis.