HESI A2 Version 3 Complete Exam 2025 – Grammar,
Math, Reading, Biology, Vocabulary, Chemistry,
Anatomy & Physiology – Actual Exam Questions and
Detailed Correct Answers (Already Graded A+)
SECTION 1 – READING COMPREHENSION
Questions 1–15 are based on the following two passages. Read each passage carefully and then
select the best answer for every question.
PASSAGE A
(1) The human respiratory system is a marvel of biological engineering. (2) Every minute, the
diaphragm contracts and relaxes approximately twelve to twenty times, drawing air into the
lungs and then expelling it. (3) This seemingly simple action is coordinated by the medulla
oblongata, a portion of the brain-stem that monitors carbon-dioxide levels in the blood. (4)
When CO₂ rises, the medulla increases both the rate and depth of respiration. (5) Conversely,
when CO₂ falls, respiration slows. (6) This negative-feedback loop maintains homeostasis, yet it
can be overridden voluntarily for short periods—an ability that allows musicians to sustain long
notes or swimmers to remain submerged. (7) However, the body’s drive to breathe is so
powerful that voluntary suppression eventually fails. (8) In medical settings, understanding this
mechanism is critical. (9) For example, post-operative patients receiving opioid analgesics must
be monitored closely because morphine directly depresses the medulla, potentially leading to
lethal apnea.
PASSAGE B
,(1) In 1928, Alexander Fleming returned from vacation to find a mold-contaminated Petri dish
that would forever change medicine. (2) The clear zone surrounding the mold indicated the
inhibition of Staphylococcus growth, a phenomenon Fleming attributed to a substance he named
penicillin. (3) Yet penicillin’s journey from laboratory curiosity to life-saving drug was neither
swift nor solitary. (4) A decade passed before a team of Oxford scientists—Howard Florey,
Ernst Chain, and Norman Heatley—devised methods to purify and mass-produce it. (5) By
1944, penicillin was being manufactured in time for the D-Day invasion, reducing Allied deaths
from infected wounds by more than eighty percent. (6) The antibiotic era had dawned, but its
success bred complacency. (7) Within four years of widespread use, penicillin-resistant
Staphylococcus emerged, underscoring an evolutionary arms race that continues today.
Which sentence from Passage A contains an opinion rather than a factual statement?
1. A. Sentence 1
B. Sentence 3
C. Sentence 6
D. Sentence 8
Correct Answer: A
Rationale: Sentence 1 (“The human respiratory system is a marvel of biological engineering”)
uses the evaluative word “marvel,” which is subjective praise rather than an objective fact. All
other choices cite sentences that present verifiable physiological mechanisms or clinical facts.
2. The author’s primary purpose in Passage A is to
A. persuade readers to avoid opioid medications
B. describe how the brain regulates breathing and its clinical relevance
C. compare human respiration with that of marine mammals
D. argue that voluntary breath control is dangerous
Correct Answer: B
Rationale: The passage focuses on medulla-driven feedback loops and ends with a clinical
application (opioid monitoring). No comparison to marine mammals is made (C), and the author
never argues against opioids in general (A) or claims breath control is inherently dangerous (D).
, 3. In Passage A, which of the following is NOT listed as a factor that can voluntarily alter
respiration?
A. Playing a musical instrument
B. Swimming under water
C. Meditating to slow heart rate
D. Suppressing the urge to breathe
Correct Answer: C
Rationale: Meditation is never mentioned. Sentence 6 explicitly cites musicians and swimmers;
“voluntary suppression” is also referenced.
4. What is the meaning of the word “depresses” in sentence 9 of Passage A?
A. Saddens emotionally
B. Lowers functionally
C. Pushes downward physically
D. Discourages verbally
Correct Answer: B
Rationale: In a medical context “depresses” means to reduce or slow activity of the medulla.
The other definitions are non-physiological.
5. Which statement best summarizes the central idea of Passage B?
A. Fleming discovered penicillin by accident and immediately saved millions.
B. Scientific breakthroughs require both serendipity and collaborative effort over time.
C. Oxford scientists stole credit from Fleming.
D. Antibiotics are no longer effective because of misuse.
Correct Answer: B
Rationale: The passage highlights accidental discovery (serendipity) plus the decade-long Oxford
teamwork needed for mass production. Choice A ignores the delay; C is unsupported; D
overgeneralizes.
6. According to Passage B, which event occurred first chronologically?
A. D-Day manufacturing of penicillin
B. Fleming’s vacation return in 1928
, C. Identification of resistant Staphylococcus
D. Oxford team purification methods
Correct Answer: B
Rationale: Sentence 1 places Fleming’s 1928 observation first. The other events followed.
7. The phrase “evolutionary arms race” in sentence 7 of Passage B refers to
A. competition between pharmaceutical companies
B. bacteria developing resistance in response to antibiotic use
C. military use of antibiotics during World War II
D. scientists racing to discover new molds
Correct Answer: B
Rationale: The immediate context is emergence of resistant bacteria, an evolutionary response.
8. Which conclusion is supported by BOTH passages?
A. Scientific progress can quickly become life-threatening.
B. Biological systems achieve balance through feedback mechanisms.
C. Medical innovations carry unintended consequences.
D. Brain chemistry controls all human behavior.
Correct Answer: C
Rationale: Passage A shows opioids can depress respiration; Passage B shows antibiotics bred
resistance—both unintended. Only Passage A discusses feedback (B), and “all behavior” (D) is
extreme.
9. Passage B implies that without Florey, Chain, and Heatley, penicillin would most likely
have
A. remained an academic footnote
B. been discovered by another team within a year
C. caused a worldwide epidemic
D. replaced all other antibiotics
Correct Answer: A
Math, Reading, Biology, Vocabulary, Chemistry,
Anatomy & Physiology – Actual Exam Questions and
Detailed Correct Answers (Already Graded A+)
SECTION 1 – READING COMPREHENSION
Questions 1–15 are based on the following two passages. Read each passage carefully and then
select the best answer for every question.
PASSAGE A
(1) The human respiratory system is a marvel of biological engineering. (2) Every minute, the
diaphragm contracts and relaxes approximately twelve to twenty times, drawing air into the
lungs and then expelling it. (3) This seemingly simple action is coordinated by the medulla
oblongata, a portion of the brain-stem that monitors carbon-dioxide levels in the blood. (4)
When CO₂ rises, the medulla increases both the rate and depth of respiration. (5) Conversely,
when CO₂ falls, respiration slows. (6) This negative-feedback loop maintains homeostasis, yet it
can be overridden voluntarily for short periods—an ability that allows musicians to sustain long
notes or swimmers to remain submerged. (7) However, the body’s drive to breathe is so
powerful that voluntary suppression eventually fails. (8) In medical settings, understanding this
mechanism is critical. (9) For example, post-operative patients receiving opioid analgesics must
be monitored closely because morphine directly depresses the medulla, potentially leading to
lethal apnea.
PASSAGE B
,(1) In 1928, Alexander Fleming returned from vacation to find a mold-contaminated Petri dish
that would forever change medicine. (2) The clear zone surrounding the mold indicated the
inhibition of Staphylococcus growth, a phenomenon Fleming attributed to a substance he named
penicillin. (3) Yet penicillin’s journey from laboratory curiosity to life-saving drug was neither
swift nor solitary. (4) A decade passed before a team of Oxford scientists—Howard Florey,
Ernst Chain, and Norman Heatley—devised methods to purify and mass-produce it. (5) By
1944, penicillin was being manufactured in time for the D-Day invasion, reducing Allied deaths
from infected wounds by more than eighty percent. (6) The antibiotic era had dawned, but its
success bred complacency. (7) Within four years of widespread use, penicillin-resistant
Staphylococcus emerged, underscoring an evolutionary arms race that continues today.
Which sentence from Passage A contains an opinion rather than a factual statement?
1. A. Sentence 1
B. Sentence 3
C. Sentence 6
D. Sentence 8
Correct Answer: A
Rationale: Sentence 1 (“The human respiratory system is a marvel of biological engineering”)
uses the evaluative word “marvel,” which is subjective praise rather than an objective fact. All
other choices cite sentences that present verifiable physiological mechanisms or clinical facts.
2. The author’s primary purpose in Passage A is to
A. persuade readers to avoid opioid medications
B. describe how the brain regulates breathing and its clinical relevance
C. compare human respiration with that of marine mammals
D. argue that voluntary breath control is dangerous
Correct Answer: B
Rationale: The passage focuses on medulla-driven feedback loops and ends with a clinical
application (opioid monitoring). No comparison to marine mammals is made (C), and the author
never argues against opioids in general (A) or claims breath control is inherently dangerous (D).
, 3. In Passage A, which of the following is NOT listed as a factor that can voluntarily alter
respiration?
A. Playing a musical instrument
B. Swimming under water
C. Meditating to slow heart rate
D. Suppressing the urge to breathe
Correct Answer: C
Rationale: Meditation is never mentioned. Sentence 6 explicitly cites musicians and swimmers;
“voluntary suppression” is also referenced.
4. What is the meaning of the word “depresses” in sentence 9 of Passage A?
A. Saddens emotionally
B. Lowers functionally
C. Pushes downward physically
D. Discourages verbally
Correct Answer: B
Rationale: In a medical context “depresses” means to reduce or slow activity of the medulla.
The other definitions are non-physiological.
5. Which statement best summarizes the central idea of Passage B?
A. Fleming discovered penicillin by accident and immediately saved millions.
B. Scientific breakthroughs require both serendipity and collaborative effort over time.
C. Oxford scientists stole credit from Fleming.
D. Antibiotics are no longer effective because of misuse.
Correct Answer: B
Rationale: The passage highlights accidental discovery (serendipity) plus the decade-long Oxford
teamwork needed for mass production. Choice A ignores the delay; C is unsupported; D
overgeneralizes.
6. According to Passage B, which event occurred first chronologically?
A. D-Day manufacturing of penicillin
B. Fleming’s vacation return in 1928
, C. Identification of resistant Staphylococcus
D. Oxford team purification methods
Correct Answer: B
Rationale: Sentence 1 places Fleming’s 1928 observation first. The other events followed.
7. The phrase “evolutionary arms race” in sentence 7 of Passage B refers to
A. competition between pharmaceutical companies
B. bacteria developing resistance in response to antibiotic use
C. military use of antibiotics during World War II
D. scientists racing to discover new molds
Correct Answer: B
Rationale: The immediate context is emergence of resistant bacteria, an evolutionary response.
8. Which conclusion is supported by BOTH passages?
A. Scientific progress can quickly become life-threatening.
B. Biological systems achieve balance through feedback mechanisms.
C. Medical innovations carry unintended consequences.
D. Brain chemistry controls all human behavior.
Correct Answer: C
Rationale: Passage A shows opioids can depress respiration; Passage B shows antibiotics bred
resistance—both unintended. Only Passage A discusses feedback (B), and “all behavior” (D) is
extreme.
9. Passage B implies that without Florey, Chain, and Heatley, penicillin would most likely
have
A. remained an academic footnote
B. been discovered by another team within a year
C. caused a worldwide epidemic
D. replaced all other antibiotics
Correct Answer: A
