"<span>Let's start with the basics: you have
probably heard that your body is 90% (or 85% or 95%) water. In actual
fact, water is (probably--unless you are obese) the majority of your
body weight--but nowhere near 90%. The best estimate I have seen is 57%
(Body water). So that puts hydrogen and oxygen in the top four.
As
I mentioned, extremely obese people can be less than 50% water. Fat
(triglycerides) is composed of carbon, hydrogen, and oxygen. The
majority of the mass of a triglyceride is carbon--chemically it is
closely related to biodiesel. So that puts carbon in the top four.
Finally,
amino acids which make up proteins (which make up muscle) require
nitrogen. That makes the top four.: Oxygen, Carbon, Hydrogen, and
Nitrogen.
But wait! What about bones? Aren't they calcium and phosphorous? Bones are really heavy.
It
turns out that calcium and phosphorous are indeed the next two most
abundant (by mass) elements in the body, but where nitrogen is about 3%
of your body mass, calcium and phosphorous are 1.5% and 1.2%
respectively.
You can find the full breakdown of the elemental composition of your body here: <span>Abundance of the chemical elements"
</span></span>
A because a primary source is defined as a first hand account of an event .
A field force is a force that acts equally on all the items in it. For example, the force you exert on the chair when you push it acts only on the chair - not on the table, other chairs, etc. around it. Whereas a force like gravity acts equally on everything - on the apple, on the leaves, on the other apples in the tree, etc
B. An equal amount of protons and electrons