What is the small unit of matter that has characteristics properties of this element?

The smallest unit of matter that has the characteristic properties of it’s element is called an “atom”.

Individual atoms are called “elements” for that reason.

There are smaller divisions of matter, however those no longer have the characteristics of the element that they may be a part of. A hydrogen electron is indistinguishable from an argon electron, or any other.

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation:

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.