In all organisms, the basic unit of structure and function is:
The cell.
The molecule.
The atom.
The macromolecule.
The Correct Answer is A
The cell is the basic unit of structure and function of all known living organisms.
The cell theory states that all living things are composed of cells and that new cells are made from preexisting cells.
Cells are organized from atoms, molecules, and macromolecules, and contain organelles that perform specialized functions.
Choice B is wrong because a molecule is a group of atoms bonded together, not a living unit.
Choice C is wrong because an atom is the smallest unit of matter, not a living unit.
Choice D is wrong because a macromolecule is a large molecule composed of smaller molecules, not a living unit.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Atrial natriuretic peptide (ANP) is a hormone secreted by the heart when the atria are stretched by high blood pressure or volume.

ANP has multiple effects, such as increasing urine and salt excretion, lowering blood pressure, and opposing the renin-angiotensin-aldosterone system.
Therefore, ANP inhibits the release of renin and aldosterone, which are hormones that increase blood pressure and sodium retention.
Choice A is wrong because ANP is not released from the adrenal cortex but from the cardiac atria.
ANP does not stimulate atrial hormones but rather inhibits them.
Choice B is wrong because ANP is not stimulated to release when blood volume decreases, but when it increases.
ANP acts to reduce blood volume by promoting diuresis and natriuresis.
Choice C is wrong because ANP does not raise blood pressure, but lowers it. ANP acts as a vasodilator and reduces peripheral resistance.
Correct Answer is A
Explanation
The fibrous pericardium is the loose-fitting sac around the heart that protects it and anchors it to surrounding structures.

Choice B is wrong because the epicardium is the outer layer of the heart wall, also called the visceral pericardium, and it is not a sac.
Choice C is wrong because the endocardium is the inner layer of the heart wall that forms the lining of all heart chambers, and it is not a sac.
Choice D is wrong because the visceral pericardium is another name for the epicardium, and it is not a loose-fitting sac.
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