select the word or phrase that makes the following sentence grammatically correct two students the machine while the third oversaw their work

HESI A2

Grammar for HESI A2

1. Select the word or phrase that makes the following sentence grammatically correct. Two students ___________ the machine while the third oversaw their work.

A. operate
B. operating
C. were operating
D. has been operating

Correct answer: A

Rationale: The word 'operate' is the correct choice as it agrees with the verb tense used in the sentence. In this case, the sentence requires the simple past tense. The correct form should be 'Two students operate the machine while the third oversaw their work.' Choices B, C, and D are incorrect because they do not match the required verb tense for the sentence. 'Operating' (choice B) is a present participle, 'were operating' (choice C) is past continuous, and 'has been operating' (choice D) is present perfect continuous, none of which fit the context of the sentence.

2. What does Elevate mean?

A. To lower
B. To lift up or place in a higher position
C. To flatten
D. To remove

Correct answer: B

Rationale: The correct answer is B: 'To lift up or place in a higher position.' Elevate means to raise something to a higher level or position. Choice A, 'To lower,' is incorrect as it is the opposite of elevate. Choice C, 'To flatten,' is incorrect as it means to make something level or smooth, not to raise it. Choice D, 'To remove,' is also incorrect as it means to take something away, not to lift or raise it.

3. Capillarity describes the tendency of fluids to rise or fall in narrow tubes. This phenomenon arises from the interplay of:

A. Buoyancy and pressure differentials
B. Density variations and compressibility of the fluid
C. Viscous dissipation and inertial effects
D. Surface tension at the liquid-gas interface and intermolecular forces

Correct answer: D

Rationale: Capillarity occurs due to surface tension and intermolecular forces between the liquid and the walls of the narrow tube. These forces cause the liquid to rise or fall depending on the cohesion and adhesion properties. Surface tension at the liquid-gas interface and intermolecular forces are responsible for capillary action, making choice D the correct answer. Choices A, B, and C are incorrect as they do not directly relate to the specific forces involved in capillarity.

4. A common example of a shear-thinning (non-Newtonian) fluid is:

A. Water
B. Ketchup
C. Air
D. Alcohol

Correct answer: B

Rationale: The correct answer is B: Ketchup. Shear-thinning fluids become less viscous under stress. Ketchup is an example of a shear-thinning fluid because its viscosity decreases when it is shaken or squeezed, allowing it to flow more easily. Choice A, Water, is a Newtonian fluid with a constant viscosity regardless of stress. Choice C, Air, is also a Newtonian fluid. Choice D, Alcohol, does not exhibit shear-thinning behavior; it typically has a constant viscosity as well.

5. Which of the following is an organ of the respiratory system?

A. Brain
B. Larynx
C. Urethra
D. Pancreas

Correct answer: B

Rationale: The larynx is an essential organ of the respiratory system. It plays a crucial role in producing sound, protecting the trachea from food aspiration, and regulating the airflow to and from the lungs. The brain is part of the nervous system, the urethra is part of the urinary system, and the pancreas is part of the digestive system. Therefore, they are not directly related to the respiratory system's functions.