Double fertilization: one sperm fuses with egg nucleus → zygote (diploid); second sperm fuses with central cell → endosperm (triploid). Unique to angiosperms.
Q.2Hard
The most advanced characters of angiosperms include all EXCEPT:
Answer: D
Angiosperms have stationary male gametes (non-motile sperm). Motile sperms are primitive characters found in bryophytes and some gymnosperms.
Q.3Hard
Which of the following statements about spores and seeds is CORRECT?
Answer: B
Spores are haploid products of meiosis; seeds contain a diploid embryo, endosperm, and seed coat. Seeds are more advanced structures for dispersal.
Q.4Hard
The most recent evolutionary advancement in plant kingdom is:
Answer: C
Flowers and fruits are the most recent evolutionary advancements (approximately 140-150 million years ago), making angiosperms the most evolved plants.
Q.5Hard
Dicots differ from monocots in all the following EXCEPT:
Answer: C
Both dicots and monocots possess vascular tissue. They differ in cotyledon number (2 vs 1), bundle arrangement, and floral parts (mostly in whorls of 4-5 vs 3).
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Q.6Hard
Which of the following plant groups shows the most complete transition from aquatic to terrestrial adaptation?
Answer: C
The transition from pteridophytes to gymnosperms shows complete terrestrial adaptation through development of pollen (no free sperm in water) and seeds (no gametophyte dependence).
Q.7Hard
Carpellary placentation where ovules are attached along the margins of the carpel is called:
Answer: C
Marginal placentation occurs when ovules develop along the ventral suture (margins) of the carpel, commonly seen in legumes.
Q.8Hard
In the plant kingdom, which pair correctly matches the plant group with its characteristic reproductive structure?
Answer: C
Bryophytes produce both archegonia (female) and antheridia (male), allowing sexual reproduction; pteridophytes, gymnosperms also have these, but bryophytes are distinctively defined by them.
Q.9Hard
The occurrence of multiple embryos from a single fertilized ovule is called:
Answer: B
Polyembryony can occur through cleavage of the proembryo, budding from integuments or nucellus, or through apomixis. This is a diverse phenomenon.
Q.10Hard
The phenomenon of seed dormancy in gymnosperms is primarily controlled by:
Answer: C
Seed dormancy is controlled by the balance between inhibitory hormones (ABA) and promoting hormones (gibberellins), along with environmental factors.
Q.11Hard
The development of the female gametophyte (embryo sac) in angiosperms typically involves:
Answer: A
In typical polygonum type, a functional megaspore undergoes three mitotic divisions producing an 8-nucleate, 7-celled embryo sac (3 antipodal, 2 synergid, 2 polar nuclei, 1 egg).
Q.12Hard
Rhynia and Cooksonia are considered primitive land plants. Their fossils are found in which geological period?
Answer: B
Rhynia and Cooksonia fossils are from the Silurian period, representing early vascular plants with primitive conducting tissues.
Q.13Hard
The phenomenon of polyembryony in angiosperms can result from which of the following?
Answer: B
Polyembryony occurs through apomixis (asexual reproduction) and cleavage polyembryony where the embryo sac or embryo divides to form multiple embryos.
Q.14Hard
The phenomenon where the endosperm provides nutrition to the developing embryo is called:
Answer: D
As the endosperm develops and stores nutrients, the nucellus degenerates, allowing the endosperm to provide nutrition directly to the embryo through absorptive cells.
Q.15Hard
A student observes a moss colony showing a 3D cushion-like structure. Which adaptation does this morphology represent?
Answer: B
The cushion-like growth form in mosses helps in water retention, provides mechanical support without vascular tissue, and increases surface area for photosynthesis and water absorption.
Q.16Hard
Which of the following represents the correct sequence of ploidy levels in the life cycle of angiosperms?
Answer: B
In angiosperms, the diploid sporophyte produces haploid spores through meiosis, which develop into haploid gametophytes that produce haploid gametes.
Q.17Hard
The phenomenon of heterospory in some pteridophytes (Selaginella) is significant because it:
Answer: D
Heterospory in Selaginella produces microspores (male) and megaspores (female), representing an evolutionary step toward seeds, and megaspores can produce female gametophytes that are partially protected, reducing water dependence for fertilization.
Q.18Hard
In gymnosperms, the integration of the female gametophyte within the ovule indicates:
Answer: D
The integration of female gametophyte (nucellus tissue) within the ovule in gymnosperms shows reduction of gametophytic independence and represents a major evolutionary transition from pteridophytes to seed plants.
Q.19Hard
Considering the evolutionary trends from bryophytes to angiosperms, which sequence is accurate?
Answer: A
The evolutionary trend shows progressive increase in sporophytic dominance, development of xylem-phloem in pteridophytes, transition to seed production in gymnosperms, and finally evolution of flowers in angiosperms.
Q.20Hard
In Pinus (Pine tree), the mature male gametophyte before pollination consists of:
Answer: B
In gymnosperms like Pinus, the mature male gametophyte (pollen grain) at the time of pollination contains 2 vegetative cells (tube cell and prothallial cell) and 1 generative cell that later divides to form sperm cells.
