1. What is the main source of energy fixed by green plants during photosynthesis?
A.
Sunlight
B.
Sound energy
C.
Wind energy
D.
Magnetic energy
Correct Answer:
Sunlight
Explanation:
Green plants fix solar energy by using sunlight to convert carbon dioxide and water into organic food during photosynthesis.
2. Which pigment primarily captures light energy for photosynthesis in green plants?
A.
Chlorophyll
B.
Hemoglobin
C.
Keratin
D.
Melanin
Correct Answer:
Chlorophyll
Explanation:
Chlorophyll absorbs light energy and helps convert it into chemical energy during photosynthesis.
3. In photosynthesis, light energy is mainly converted into which form of energy?
A.
Chemical energy
B.
Sound energy
C.
Mechanical energy
D.
Nuclear energy
Correct Answer:
Chemical energy
Explanation:
During energy fixation, plants store captured light energy as chemical energy in organic compounds such as glucose.
4. Which organisms are mainly responsible for fixing solar energy in an ecosystem?
A.
Green plants
B.
Herbivores
C.
Carnivores
D.
Decomposers
Correct Answer:
Green plants
Explanation:
Green plants contain chlorophyll and fix solar energy through photosynthesis, forming the primary source of energy for most ecosystems.
5. What is the immediate energy-rich product formed during the light reactions of photosynthesis?
A.
ATP
B.
Urea
C.
Lactic acid
D.
Cellulose
Correct Answer:
ATP
Explanation:
The light reactions produce ATP, which temporarily stores and transfers the captured energy for use in carbon fixation.
6. Which gas is incorporated into organic matter during carbon fixation in photosynthesis?
A.
Carbon dioxide
B.
Oxygen
C.
Nitrogen
D.
Hydrogen
Correct Answer:
Carbon dioxide
Explanation:
Carbon dioxide is fixed into organic compounds during photosynthesis, using energy captured from sunlight.
7. Which type of organisms can fix energy using chemical substances instead of sunlight?
A.
Chemosynthetic bacteria
B.
Herbivorous mammals
C.
Parasitic worms
D.
Insectivorous birds
Correct Answer:
Chemosynthetic bacteria
Explanation:
Chemosynthetic bacteria obtain energy by oxidizing inorganic substances and use that energy to form organic matter.
8. The fixation of solar energy by plants results in the formation of what kind of matter?
A.
Organic matter
B.
Only mineral salts
C.
Only water
D.
Only oxygen gas
Correct Answer:
Organic matter
Explanation:
Plants use fixed solar energy to synthesize organic compounds such as carbohydrates from inorganic substances.
9. Where does the light energy used for photosynthetic energy fixation originate?
A.
The Sun
B.
The soil
C.
The Moon
D.
The atmosphere alone
Correct Answer:
The Sun
Explanation:
The Sun provides the light energy that chlorophyll captures and converts into chemical energy during photosynthesis.
10. Why is energy fixation by producers important in an ecosystem?
A.
It introduces usable energy into the food chain
B.
It removes all oxygen from the atmosphere
C.
It stops the formation of organic matter
D.
It prevents energy transfer to consumers
Correct Answer:
It introduces usable energy into the food chain
Explanation:
Producers fix solar or chemical energy into organic matter, making energy available to herbivores and other organisms in the ecosystem.
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