The membranes that line the tubes or cavities that have openings to the external environment are referred to as _____.

How many cells does the human body have?

_____are the functional units of nervetissue.

When placed in water, ionic substances ionize into _____.

The number of protons plus the number of neutrons determines the _____ of an atom.

_____lack(s) striations and are(is) involuntary.

The connective tissue that helps insulate the body, cushions internal organs, and stores excess nutrient energy is _____tissue.

A monounsaturated fat would have _____.

The ionization of a/an _____ releases hydrogen ions and increases the concentration of hydrogen ions in a solution.

Covalent bonds form when _____.