An introduction is the first set of information it is found at the beginning of your portfolio. The goal of your introduction is to explain to the reader what the
topic is about and what your portfolio is all about. Your introduction lets your
readers know what you hope to achieve and what they can expect from your
assignment.
The introduction is a brief paragraph which should be not be longer than one (1)
paragraph.

Why  do you think body composition focuses  on the  ratio  of  fatty tissue  to  other body tissue? why is  body composition not related  to  weight?

Muscles in the body us with a lot of things for example, if i wanted to lift a heavy box and had no muscle i would just collapse where i was because of the fact muscles hold us together. overall they are 650 muscle in the human body, all of them have different purposes and ways to keep us together. there are three types of muscle in the body skeletal, smooth, and cardiac muscle. skeletal muscle are attached to the bone and with movement. smooth muscle, this is found in the wall of our organs, such as our stomach, this muscle with movement   as well, without this muscle, we would only be allowed to eat small amounts. the cardiac muscle is the heart muscle and probably the most important one. these are only found in the walls of the heart and the heart pump blood to the other parts of your body. we have two different types of muscle fibers, slow twitch and fast twitch. slow twitch muscles enable long-endurance feats such as distance running. fast twitch fatigue faster but are used in powerful bursts of movements like sprinting. there are three different types of muscle contractions concentric, eccentric, isometric. concentric contraction causes muscles to shorten, thereby generating force.   eccentric contractions cause muscles to elongate in response to a greater opposing force. isometric contractions generate force without changing the length of the muscle.: //athleticquickness.com/muscle-contraction-types-part-1/

There is tumerous cancer, kawaski disease and more.