ESTUDYR
BIO-105 EXAM #1 2025 MULTICHOICE ANSWERED
EXAM QUESTIONS WITH DETAILED RATIONALES
Biology is best defined as:
A. The study of only human anatomy
B. The study of rocks and minerals
C. ✔ The study of living organisms and their interactions with each other and their
environments.
D. The study of the solar system
Rationale: Biology concerns life and interactions across scales.
The cell is:
A. A small rock in soil
B. ✔ The smallest fundamental unit of structure and function in living things.
C. A type of organ
D. An ecosystem component
Rationale: Cells are the basic unit of life.
The biosphere refers to:
A. A single organism’s habitat
B. ✔ The global collection of all living organisms on Earth.
C. Only ocean life zones
D. The gaseous layer of Earth
Rationale: Biosphere = all life on Earth and their environments.
A community in ecology is:
A. One single species population
B. ✔ A set of interacting populations of different species in a particular area.
C. All abiotic elements in an area
D. A single organism’s organ system
Rationale: Community = multiple populations coexisting and interacting.
An ecosystem includes:
A. Only plants in a region
B. ✔ All living organisms in an area plus the abiotic (nonliving) components.
C. Only the soil of a habitat
D. Only the energy flows, not organisms
Rationale: Ecosystems integrate biotic and abiotic factors.
, ESTUDYR
Homeostasis is:
A. Rapid mutation in a population
B. ✔ The ability of an organism to maintain stable internal conditions.
C. The formation of fossils
D. Species formation
Rationale: Homeostasis preserves internal balance despite external changes.
A macromolecule is:
A. A tiny ion
B. ✔ A very large molecule formed by joining smaller monomers (e.g., proteins,
polysaccharides).
C. Always inorganic
D. A single atom
Rationale: Macromolecules = large biomolecules built from monomers.
A molecule is:
A. A field of study
B. ✔ A chemical structure of two or more atoms held together by bonds.
C. A type of cell
D. A membrane protein
Rationale: Molecules are bonded atoms forming substances.
An organ is:
A. A single cell type only
B. ✔ A structure made of multiple tissues that performs a specific function.
C. A group of organs in the body
D. A molecule of DNA
Rationale: Organs are tissue assemblies performing functions.
An organ system is:
A. A single tissue
B. ✔ A set of organs that work together for a common function.
C. A group of cells identical in shape
D. A DNA sequence
Rationale: Organ systems coordinate multiple organs (e.g., digestive).
An organelle is:
A. An individual organism
B. ✔ A membrane-bound structure within a cell that performs a specialized function.
C. A tissue type
BIO-105 EXAM #1 2025 MULTICHOICE ANSWERED
EXAM QUESTIONS WITH DETAILED RATIONALES
Biology is best defined as:
A. The study of only human anatomy
B. The study of rocks and minerals
C. ✔ The study of living organisms and their interactions with each other and their
environments.
D. The study of the solar system
Rationale: Biology concerns life and interactions across scales.
The cell is:
A. A small rock in soil
B. ✔ The smallest fundamental unit of structure and function in living things.
C. A type of organ
D. An ecosystem component
Rationale: Cells are the basic unit of life.
The biosphere refers to:
A. A single organism’s habitat
B. ✔ The global collection of all living organisms on Earth.
C. Only ocean life zones
D. The gaseous layer of Earth
Rationale: Biosphere = all life on Earth and their environments.
A community in ecology is:
A. One single species population
B. ✔ A set of interacting populations of different species in a particular area.
C. All abiotic elements in an area
D. A single organism’s organ system
Rationale: Community = multiple populations coexisting and interacting.
An ecosystem includes:
A. Only plants in a region
B. ✔ All living organisms in an area plus the abiotic (nonliving) components.
C. Only the soil of a habitat
D. Only the energy flows, not organisms
Rationale: Ecosystems integrate biotic and abiotic factors.
, ESTUDYR
Homeostasis is:
A. Rapid mutation in a population
B. ✔ The ability of an organism to maintain stable internal conditions.
C. The formation of fossils
D. Species formation
Rationale: Homeostasis preserves internal balance despite external changes.
A macromolecule is:
A. A tiny ion
B. ✔ A very large molecule formed by joining smaller monomers (e.g., proteins,
polysaccharides).
C. Always inorganic
D. A single atom
Rationale: Macromolecules = large biomolecules built from monomers.
A molecule is:
A. A field of study
B. ✔ A chemical structure of two or more atoms held together by bonds.
C. A type of cell
D. A membrane protein
Rationale: Molecules are bonded atoms forming substances.
An organ is:
A. A single cell type only
B. ✔ A structure made of multiple tissues that performs a specific function.
C. A group of organs in the body
D. A molecule of DNA
Rationale: Organs are tissue assemblies performing functions.
An organ system is:
A. A single tissue
B. ✔ A set of organs that work together for a common function.
C. A group of cells identical in shape
D. A DNA sequence
Rationale: Organ systems coordinate multiple organs (e.g., digestive).
An organelle is:
A. An individual organism
B. ✔ A membrane-bound structure within a cell that performs a specialized function.
C. A tissue type
