Questions on Plants: Importance and Plant Life Cycle
Multiple-Choice Questions – Importance of Plants and Plant Life Cycle
1. Which of the following best describes the main role of plants in an ecosystem?
A) Predators of insects
B) Producers of oxygen and organic matter
C) Primary consumers
D) Decomposers of dead organisms
E) Parasites on other species
2. Plants are crucial in the carbon cycle because they:
A) Produce fossil fuels
B) Emit carbon dioxide
C) Fix atmospheric nitrogen
D) Absorb and store carbon dioxide
E) Break down rock into soil
3. The process by which plants convert sunlight into chemical energy is called:
A) Respiration
B) Transpiration
C) Photosynthesis
D) Germination
E) Fermentation
4. Which gas is absorbed by plants during photosynthesis?
A) Nitrogen
B) Oxygen
C) Methane
D) Carbon dioxide
E) Hydrogen
5. The main product of photosynthesis is:
A) Oxygen
B) Glucose
C) Water
D) Carbon dioxide
E) Nitrogen
6. Plants help prevent soil erosion by:
A) Absorbing sunlight
B) Fixing nitrogen
C) Holding the soil with their roots
D) Releasing oxygen
E) Removing salt from the soil
7. Which part of the plant anchors it to the ground and absorbs water?
A) Leaf
B) Stem
C) Root
D) Flower
E) Fruit
8. The plant life cycle alternates between:
A) Sexual and asexual reproduction
B) Fertilization and germination
C) Gametophyte and sporophyte generations
D) Seeds and flowers
E) Roots and shoots
9. In the plant life cycle, the gametophyte produces:
A) Spores
B) Flowers
C) Fruits
D) Gametes
E) Seeds
10. What happens after fertilization in the plant life cycle?
A) The plant dies
B) The flower opens
C) The seed develops
D) The plant photosynthesizes
E) Leaves fall off
11. Seeds are primarily formed by:
A) Pollination
B) Spore germination
C) Asexual reproduction
D) Fertilization of ovules
E) Root development
12. The transfer of pollen from the anther to the stigma is called:
A) Germination
B) Fertilization
C) Pollination
D) Division
E) Reproduction
13. In angiosperms, fertilization occurs in the:
A) Stigma
B) Style
C) Ovary
D) Anther
E) Sepal
14. Which part of the plant life cycle is haploid?
A) Sporophyte
B) Zygote
C) Gametophyte
D) Embryo
E) Mature plant
15. The part of the plant responsible for reproduction is the:
A) Leaf
B) Root
C) Stem
D) Flower
E) Bark
16. What is the role of fruit in plant reproduction?
A) Photosynthesis
B) Storage of water
C) Seed protection and dispersal
D) Support for the flower
E) Root growth
17. Which of the following is a reason why plants are important to humans?
A) They produce fossil fuels
B) They destroy ozone
C) They provide oxygen and food
D) They reduce biodiversity
E) They compete with animals
18. Which process allows a seed to begin growing into a plant?
A) Germination
B) Fertilization
C) Pollination
D) Respiration
E) Photosynthesis
19. In which plant organ does photosynthesis primarily occur?
A) Flower
B) Stem
C) Root
D) Leaf
E) Seed
20. What is the function of chlorophyll in plants?
A) Absorbs carbon dioxide
B) Stores food
C) Absorbs sunlight for photosynthesis
D) Transports nutrients
E) Stimulates growth
21. Which plant part typically contains both male and female reproductive structures in flowering plants?
A) Leaf
B) Stem
C) Root
D) Flower
E) Fruit
22. Which of the following is a true statement about plant life cycles?
A) They include only diploid stages
B) Only angiosperms have a gametophyte stage
C) Spores and seeds are the same
D) Alternation of generations is typical
E) Gametophytes are always larger than sporophytes
23. The embryo within a seed is formed by:
A) Mitosis of the ovary
B) Meiosis of the pollen grain
C) Fertilization of gametes
D) Germination of spores
E) Growth of the stem
24. Which of the following best explains why plants are called "primary producers"?
A) They live in the soil
B) They eat other organisms
C) They make their own food and support food webs
D) They are the first to decompose
E) They pollinate other plants
25. Which of these organisms directly depend on plants for survival?
A) Herbivores
B) Carnivores
C) Decomposers
D) Humans
E) All of the above
Answer Key with Explanations
1. B – Plants are primary producers that produce oxygen and organic matter.
2. D – Plants absorb CO₂ during photosynthesis, reducing atmospheric carbon.
3. C – Photosynthesis converts sunlight into chemical energy.
4. D – CO₂ is the gas taken in by plants during photosynthesis.
5. B – Glucose is the main energy-rich product of photosynthesis.
6. C – Roots hold the soil and prevent erosion.
7. C – Roots anchor the plant and absorb water/nutrients.
8. C – Plant life cycles alternate between haploid gametophyte and diploid sporophyte.
9. D – Gametophytes produce gametes (sperm and egg).
10. C – Fertilization leads to the development of a seed.
11. D – Seeds are formed after fertilization of ovules in flowers.
12. C – Pollination is the transfer of pollen to the stigma.
13. C – Fertilization occurs in the ovary where ovules are housed.
14. C – The gametophyte generation is haploid.
15. D – Flowers contain the reproductive structures.
16. C – Fruits protect seeds and aid in their dispersal.
17. C – Plants supply oxygen and are major food sources.
18. A – Germination is the process where a seed grows into a new plant.
19. D – Most photosynthesis occurs in the leaves.
20. C – Chlorophyll captures sunlight for photosynthesis.
21. D – Flowers often contain both stamens (male) and carpels (female).
22. D – Most plants alternate between sporophyte and gametophyte stages.
23. C – The fusion of gametes forms the seed's embryo.
24. C – Plants are autotrophs and form the base of food chains.
25. E – All organisms (herbivores, carnivores, decomposers, humans) rely on plants directly or indirectly
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