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 C
Explanation
This is because the external jugular vein drains blood from the face and scalp into the subclavian vein.
Some possible explanations for the other choices are:
Choice A. Superior vena cava.
This is wrong because the superior vena cava is a large vein that collects blood from the head, neck, chest, and upper limbs and returns it to the right atrium of the heart.
It does not drain blood from the face and scalp directly.
Choice B. Subclavian vein.
This is wrong because the subclavian vein is a vein that receives blood from the external jugular vein, the internal jugular vein, and the vertebral vein and joins with the internal thoracic vein to form the brachiocephalic vein.
It does not drain blood from the face and scalp directly.
Choice D. Cephalic vein.
This is wrong because the cephalic vein is a vein that runs along the lateral side of the arm from the hand to the shoulder and empties into the axillary vein.
It does not drain blood from the face and scalp at all.
Normal ranges for blood pressure vary depending on age, gender, health status, and other factors, but a general guideline is that systolic blood pressure (the pressure when the heart contracts) should be less than 120 mmHg and diastolic blood pressure (the pressure when the heart relaxes) should be less than 80 mmHg.
Correct Answer is B
Explanation
This means that the electrical activity that causes the atria to contract starts from the sinoatrial node and spreads across the atria.
The P wave on the ECG reflects this atrial depolarization.
Choice A is wrong because repolarization of atrial muscle fibers is not visible on the ECG, as it occurs during the QRS complex when the ventricular depolarization masks it.
Choice C is wrong because the depolarization of ventricular muscle fibers is represented by the QRS complex on the ECG, not the P wave.
Choice D is wrong because the repolarization of ventricular muscle fibers is represented by the T wave on the ECG, not the P wave.
Normal ranges for the P wave are:
Duration: less than 0.12 seconds (less than 3 small squares)
Amplitude: less than 2.5 mm (0.25 mV) in the limb leads, less than 1.5 mm (0.15 mV) in the precordial leads
Axis: between 0° and +75°12
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