CSS - PMS - CCE - PCS - General Science
Ecosystem
What are producers in an ecosystem?
A. Parasites only
B. Organisms that only decompose dead matter
C. Animals that eat plants only
D. Organisms that make organic food from inorganic materials, usually by photosynthesis
Correct Answer: D
Primary producers convert light or chemical energy into organic matter.
CSS - PMS - CCE - PCS - General Science
Ecosystem
Which is an abiotic component of an ecosystem?
A. Plants
B. Fungi
C. Bacteria
D. Temperature
Correct Answer: D
Abiotic components are nonliving physical or chemical factors.
CSS - PMS - CCE - PCS - General Science
Ecosystem
Which is a biotic component of an ecosystem?
A. Sunlight
B. Plants
C. Water
D. Temperature
Correct Answer: B
Biotic components are living organisms.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What is an ecosystem?
A. A community of organisms interacting with each other and with the nonliving environment
B. Only soil and rocks
C. A single organism
D. Only the animals in a forest
Correct Answer: A
An ecosystem includes biotic communities and abiotic environmental components.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which structure is present in plant cells but absent from animal cells and provides rigid support?
A. Cytoplasm
B. Ribosome
C. Plasma membrane
D. Cell wall
Correct Answer: D
Plant cell walls, largely made of cellulose, provide mechanical support.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which organelle contains digestive enzymes and helps break down cellular waste?
A. Nucleus
B. Ribosome
C. Centriole only
D. Lysosome
Correct Answer: D
Lysosomes contain hydrolytic enzymes for intracellular digestion.
CSS - PMS - CCE - PCS - General Science
Cell Biology
What is osmosis?
A. Net movement of water across a selectively permeable membrane from higher water potential to lower water potential
B. Breakdown of glucose without enzymes
C. Division of a nucleus
D. Movement of proteins against gravity only
Correct Answer: A
Osmosis is passive water movement driven by differences in water potential.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which organelle carries out photosynthesis in plant cells?
A. Golgi apparatus
B. Mitochondrion only
C. Chloroplast
D. Lysosome
Correct Answer: C
Chloroplasts contain chlorophyll and photosynthetic machinery.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which structure selectively controls movement of substances into and out of the cell?
A. Cell wall only
B. Chromosome
C. Plasma membrane
D. Nucleolus
Correct Answer: C
The cell membrane is selectively permeable and regulates transport.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which organelle modifies, sorts and packages proteins for transport?
A. Chloroplast
B. Mitochondrion
C. Golgi apparatus
D. Nucleolus
Correct Answer: C
The Golgi apparatus processes and packages proteins and lipids.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which structure is the main site of protein synthesis?
A. Centrosome
B. Cell wall
C. Lysosome
D. Ribosome
Correct Answer: D
Ribosomes translate mRNA into polypeptide chains.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which organelle is the main site of ATP production by aerobic respiration?
A. Mitochondrion
B. Nucleus
C. Ribosome
D. Vacuole
Correct Answer: A
Mitochondria generate most cellular ATP through oxidative phosphorylation.
CSS - PMS - CCE - PCS - General Science
Cell Biology
Which organelle contains most of the genetic material in a eukaryotic cell?
A. Lysosome
B. Ribosome
C. Golgi apparatus
D. Nucleus
Correct Answer: D
The nucleus contains the cell's chromosomes in eukaryotes.
CSS - PMS - CCE - PCS - General Science
Cell Biology
What is the basic structural and functional unit of life?
A. Cell
B. Organ
C. Atom
D. Tissue
Correct Answer: A
All living organisms are composed of one or more cells, the basic units of life.
CSS - PMS - CCE - PCS - General Science
Biodiversity
Why is biodiversity important to ecosystem resilience?
A. It eliminates competition
B. Greater functional variety can help ecosystems withstand and recover from disturbances
C. It prevents all natural change
D. It guarantees no species ever becomes extinct
Correct Answer: B
Diverse ecosystems often possess functional redundancy and broader response capacity.
CSS - PMS - CCE - PCS - General Science
Biodiversity
What is ex-situ conservation?
A. Maintaining only wild food chains
B. Protecting a forest from logging only
C. Banning rainfall
D. Conserving species outside their natural habitats
Correct Answer: D
Seed banks, botanical gardens and captive breeding are ex-situ approaches.
CSS - PMS - CCE - PCS - General Science
Biodiversity
What is in-situ conservation?
A. Preserving rocks in museums
B. Protecting species in their natural habitats
C. Moving every species to farms
D. Storing all organisms only in laboratories
Correct Answer: B
National parks and wildlife reserves are examples of in-situ conservation.
CSS - PMS - CCE - PCS - General Science
Biodiversity
What is a biodiversity hotspot?
A. A region with exceptional endemic biodiversity that is under major threat
B. A region with constant temperature
C. Any desert with no species
D. An area used only for agriculture
Correct Answer: A
Hotspots combine high endemism with extensive habitat loss.
CSS - PMS - CCE - PCS - General Science
Biodiversity
Which human activity is a major direct driver of biodiversity loss?
A. Natural pollination
B. Photosynthesis
C. Cloud formation
D. Habitat destruction
Correct Answer: D
Habitat conversion and fragmentation are among the leading causes of species decline.
CSS - PMS - CCE - PCS - General Science
Biodiversity
What is an endemic species?
A. A species with no habitat
B. A species found everywhere on Earth
C. A domesticated species only
D. A species naturally restricted to a particular geographic area
Correct Answer: D
Endemic species have limited natural geographic distributions.