The female gametophyte in angiosperms is typically represented by the _______ stage.
Answer: B
The mature embryo sac with 7 cells (3 antipodal cells, 2 synergids, 1 egg cell, 2 polar nuclei) represents the female gametophyte in angiosperms.
Q.82Medium
Which of the following statements about alternation of generations is correct?
Answer: A
Bryophytes display clear alternation of generations with the gametophyte being the dominant, independent phase while the sporophyte is small and dependent.
Q.83Medium
A botanist observes a plant with jointed stems, scale-like leaves, and spores produced in strobili. This plant likely belongs to which division?
Answer: B
Equisetophytes (horsetails) are characterized by jointed stems with silica deposition, reduced scale-like leaves in whorls, and spores in terminal strobili.
Q.84Medium
The vascular tissue in ferns differs from that in gymnosperms primarily in which aspect?
Answer: B
Both ferns and gymnosperms lack vessels in xylem and have sieve cells instead of sieve tubes in phloem, but ferns typically have scattered vascular bundles.
Q.85Medium
Which of the following is NOT a characteristic of angiosperms compared to gymnosperms?
Answer: C
Angiosperms can be monocots (one cotyledon) or dicots (two cotyledons), so not all angiosperms have two cotyledons.
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Q.86Medium
In liverworts, the gemma cup structure primarily serves the function of:
Answer: B
Gemma cups in liverworts produce small vegetative bodies (gemmae) that are dispersed for asexual reproduction, allowing rapid colonization.
Q.87Medium
The prothallus in pteridophytes is homologous to which structure in bryophytes?
Answer: B
The prothallus (gametophyte) in pteridophytes is homologous to the gametophytic generation in bryophytes as both are haploid structures producing gametes.
Q.88Hard
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.89Hard
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.90Hard
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.91Hard
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.92Easy
Which of the following is the main evolutionary advantage of the flower in angiosperms?
Answer: B
Flowers attract pollinators through various mechanisms (color, scent, nectar) and provide protection to reproductive organs, making sexual reproduction more efficient compared to gymnosperms.
Q.93Medium
The integument in an ovule develops from:
Answer: B
The integument develops from the chalaza end of the nucellus and grows upward to cover the nucellus, leaving only the micropyle opening for pollen entry.
Q.94Medium
A research team identifies a plant with the following features: free-living sporophyte, independent gametophyte, presence of sporangia on leaf undersurface, and no seeds. This plant belongs to:
Answer: B
These characteristics are typical of pteridophytes/ferns: independent sporophyte and gametophyte, sporangia on fern fronds, and reproduction through spores without seeds.
Q.95Medium
The archegonium in bryophytes and pteridophytes is significant because it:
Answer: B
The archegonium is a flask-shaped female reproductive organ that protects the egg cell and provides a passage (neck canal) for sperm entry, requiring moisture for fertilization.
Q.96Hard
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.97Hard
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.
Q.98Medium
In bryophytes, the dominant generation is gametophytic, while in pteridophytes it shifts to sporophytic dominance. Which of the following best explains the evolutionary advantage of this transition?
Answer: D
The shift from gametophytic to sporophytic dominance in pteridophytes is advantageous because: (1) Sporophytes with indeterminate growth can produce more spores, increasing reproductive success, and (2) Spores with thick protective walls (sporopollenin) can survive in drier environments, reducing dependence on moisture. This represents a major evolutionary transition.
Q.99Easy
Which of the following characteristics is unique to gymnosperms compared to both angiosperms and pteridophytes?
Answer: B
Gymnosperms are characterized by naked ovules that are not enclosed within an ovary wall. This distinguishes them from angiosperms (which have ovules in ovaries) and pteridophytes (which lack seeds). The term 'gymnosperm' literally means 'naked seed'.
Q.100Hard
A researcher studying fossil records observes that early vascular plants (Rhyniophytes) lacked both roots and leaves but possessed a simple vascular system. Based on evolutionary trends in the Plant Kingdom, which structure would have evolved FIRST to maximize photosynthetic efficiency in these early plants?
Answer: B
In early vascular plants like Rhyniophytes, the evolution of true leaves with expanded surface area was critical for maximizing photosynthesis in terrestrial environments. Though roots evolved to access underground water, the immediate advantage for terrestrial survival was increased photosynthetic capability. True leaves with organized vascular tissue provided both structural support and efficient light capture, giving competitive advantage over earlier bryophytes.
