HESI A2
Biology HESI A2 Practice Test
1. In the scientific process, which of the following is a statement or explanation of certain events or happenings?
- A. hypothesis
- B. observation
- C. experiment
- D. conclusion
Correct answer: A
Rationale: A hypothesis is a statement or explanation of certain events or phenomena based on observations and prior knowledge. It is a testable prediction that guides the scientific investigation process. By formulating a hypothesis, scientists can make predictions and design experiments to gather data and test the validity of the hypothesis. Observations (choice B) involve gathering information through the senses. Experiments (choice C) are procedures carried out to support or refute a hypothesis. Conclusions (choice D) are deductions made based on the results of experiments and observations, but they are not the initial statement or explanation of events or happenings.
2. How many moles of potassium bromide are in 25 mL of a 4 M KBr solution?
- A. 0.035 mol
- B. 0.1 mol
- C. 0.18 mol
- D. 1.6 mol
Correct answer: B
Rationale: To find the moles of potassium bromide in 25 mL of a 4 M KBr solution, we first need to convert the volume from milliliters to liters. 25 mL is equal to 0.025 L. Then, we use the formula moles = molarity x volume in liters. Substituting the values, moles = 4 M x 0.025 L = 0.1 mol. Therefore, there are 0.1 moles of KBr in 25 mL of a 4 M solution. Choice A, 0.035 mol, is incorrect as it does not properly calculate the moles. Choice C, 0.18 mol, and choice D, 1.6 mol, are also incorrect as they are not the result of the correct calculation based on the given molarity and volume.
3. The man's heart attack scared him badly and he decided to have a regular check-up.
- A. severely
- B. badly
- C. intensely
- D. profoundly
Correct answer: B
Rationale: In this context, 'badly' is the appropriate adverb to describe the intensity of the fear caused by the heart attack. 'Severely' and 'intensely' do not convey the same meaning in this sentence. 'Profoundly' refers more to depth or seriousness of an emotion, which doesn't fit the context of fear caused by a heart attack.
4. Select the word or phrase that makes this sentence grammatically correct: 'The development committee ____ a bargain with the city planners.'
- A. striked
- B. stroke
- C. struck
- D. strike
Correct answer: C
Rationale: The correct answer is 'C: struck.' In this context, the correct verb form should be 'struck' as it is the past tense form of 'strike.' Therefore, the correct sentence should read: 'The development committee struck a bargain with the city planners.' Choice A, 'striked,' is incorrect as 'strike' is an irregular verb, and the past tense is 'struck' rather than 'striked.' Choice B, 'stroke,' is incorrect as it is not the correct past tense form of 'strike' in this context. Choice D, 'strike,' is incorrect as it is the base form of the verb and does not fit the sentence structure requiring a past tense verb.
5. What is the primary function of hemoglobin in red blood cells?
- A. To transport nutrients
- B. To fight infections
- C. To carry oxygen
- D. To produce energy
Correct answer: C
Rationale: The correct answer is C: 'To carry oxygen.' Hemoglobin in red blood cells binds to oxygen in the lungs and transports it to the tissues and organs throughout the body. This oxygen transport is crucial for cellular respiration and the overall functioning of the body. Choices A, B, and D are incorrect because hemoglobin's primary function is not to transport nutrients, fight infections, or produce energy in red blood cells.
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