RIO BIO 156 Exam 1 | 2025/2026 Verified Questions &
Correct Answers with Rationales | Graded A+
Introductory Human Biology | Key Concepts: Cell Biology, Biomolecules, Homeostasis, Body
Organization, and Genetics Foundations | Expert-Developed Q&A | 100% Exam-Ready and
Concept-Mastered
Introduction
This 2025/2026 RIO BIO 156 Exam 1 resource includes expertly written, high-yield biology
questions with correct answers and clear rationales reflecting Rio Salado College’s learning
outcomes for Introductory Human Biology. It emphasizes understanding of molecular and
cellular foundations of human life, biological chemistry, and structural organization. Each
question promotes conceptual mastery and readiness for graded coursework and exams. Covers
Chapters 1–4: Introduction to Biology, Chemistry of Life, Cell Structure & Function, and
Energy & Metabolism.
Answer Format
All correct answers will be highlighted in bold and green, followed by well-defined rationales
explaining key biological principles, ensuring clear understanding and exam confidence.
RIO BIO 156 Exam 1 – 50 Official Questions
Section 1: Introduction to Biology & Scientific Method (1–10)
1. The basic unit of life is the:
a) Atom
b) Molecule
c) Cell
d) Tissue
Answer: c) Cell
Rationale: Cell theory states all living organisms are composed of cells, and the cell is the
smallest unit capable of life functions.
2. Which is not a characteristic of life?
a) Metabolism
b) Homeostasis
c) Photosynthesis
d) Reproduction
Answer: c) Photosynthesis
Rationale: Photosynthesis is specific to autotrophs; all life exhibits metabolism, homeostasis,
growth, response to stimuli, reproduction, and evolution.
, 3. The process by which organisms maintain a stable internal environment is:
a) Metabolism
b) Homeostasis
c) Evolution
d) Adaptation
Answer: b) Homeostasis
Rationale: Negative feedback loops regulate variables like temperature, pH, and glucose within
narrow ranges.
4. In the scientific method, a hypothesis is:
a) A proven fact
b) A testable explanation
c) A final conclusion
d) An observation
Answer: b) A testable explanation
Rationale: Must be falsifiable and based on prior observations.
5. The control group in an experiment:
a) Receives the treatment
b) Is identical except for the independent variable
c) Contains the largest sample
d) Is always the first group tested
Answer: b) Is identical except for the independent variable
Rationale: Isolates the effect of the independent variable on the dependent variable.
6. The atomic number of an element represents:
a) Number of protons
b) Number of neutrons
c) Total electrons + protons
d) Mass number
Answer: a) Number of protons
Rationale: Defines the element and determines chemical properties.
7. An isotope differs in:
a) Protons
b) Electrons
c) Neutrons
d) Atomic number
Answer: c) Neutrons
Rationale: Same element, different neutron count (e.g., C-12 vs C-14).
8. The pH of blood is maintained around:
a) 5.5
b) 7.4
c) 8.0
d) 9.2
Correct Answers with Rationales | Graded A+
Introductory Human Biology | Key Concepts: Cell Biology, Biomolecules, Homeostasis, Body
Organization, and Genetics Foundations | Expert-Developed Q&A | 100% Exam-Ready and
Concept-Mastered
Introduction
This 2025/2026 RIO BIO 156 Exam 1 resource includes expertly written, high-yield biology
questions with correct answers and clear rationales reflecting Rio Salado College’s learning
outcomes for Introductory Human Biology. It emphasizes understanding of molecular and
cellular foundations of human life, biological chemistry, and structural organization. Each
question promotes conceptual mastery and readiness for graded coursework and exams. Covers
Chapters 1–4: Introduction to Biology, Chemistry of Life, Cell Structure & Function, and
Energy & Metabolism.
Answer Format
All correct answers will be highlighted in bold and green, followed by well-defined rationales
explaining key biological principles, ensuring clear understanding and exam confidence.
RIO BIO 156 Exam 1 – 50 Official Questions
Section 1: Introduction to Biology & Scientific Method (1–10)
1. The basic unit of life is the:
a) Atom
b) Molecule
c) Cell
d) Tissue
Answer: c) Cell
Rationale: Cell theory states all living organisms are composed of cells, and the cell is the
smallest unit capable of life functions.
2. Which is not a characteristic of life?
a) Metabolism
b) Homeostasis
c) Photosynthesis
d) Reproduction
Answer: c) Photosynthesis
Rationale: Photosynthesis is specific to autotrophs; all life exhibits metabolism, homeostasis,
growth, response to stimuli, reproduction, and evolution.
, 3. The process by which organisms maintain a stable internal environment is:
a) Metabolism
b) Homeostasis
c) Evolution
d) Adaptation
Answer: b) Homeostasis
Rationale: Negative feedback loops regulate variables like temperature, pH, and glucose within
narrow ranges.
4. In the scientific method, a hypothesis is:
a) A proven fact
b) A testable explanation
c) A final conclusion
d) An observation
Answer: b) A testable explanation
Rationale: Must be falsifiable and based on prior observations.
5. The control group in an experiment:
a) Receives the treatment
b) Is identical except for the independent variable
c) Contains the largest sample
d) Is always the first group tested
Answer: b) Is identical except for the independent variable
Rationale: Isolates the effect of the independent variable on the dependent variable.
6. The atomic number of an element represents:
a) Number of protons
b) Number of neutrons
c) Total electrons + protons
d) Mass number
Answer: a) Number of protons
Rationale: Defines the element and determines chemical properties.
7. An isotope differs in:
a) Protons
b) Electrons
c) Neutrons
d) Atomic number
Answer: c) Neutrons
Rationale: Same element, different neutron count (e.g., C-12 vs C-14).
8. The pH of blood is maintained around:
a) 5.5
b) 7.4
c) 8.0
d) 9.2
