The suspensor in angiosperm embryos functions primarily to:
Answer: A
The suspensor absorbs nutrients from the endosperm and pushes the developing embryo deeper into the embryo sac for better nourishment.
Q.45Medium
In bryophytes, the sperm require water for fertilization. Which adaptation in pteridophytes partially overcame this limitation?
Answer: B
Pteridophytes still require water as sperm are flagellated, but the prothallus provides a moist environment. True water independence came with seeds in gymnosperms.
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Q.46Medium
The phenomenon of apomixis in plants results in:
Answer: A
Apomixis is asexual reproduction in seeds where offspring are genetically identical to the parent, bypassing meiosis and fertilization.
Q.47Medium
Which structural adaptation in angiosperms represents the most advanced reproductive strategy?
Answer: B
Double fertilization is unique to angiosperms where one sperm nucleus fertilizes the egg (embryo) and another fertilizes the polar nuclei (endosperm), providing efficient nutrition for the developing embryo.
Q.48Medium
The phenomenon where a single flower produces both viable pollen and functional ovules is termed:
Answer: D
This represents a hermaphroditic flower with the potential for self-fertilization. Dichogamy prevents this by temporal separation, heterostyly by spatial separation.
Q.49Easy
In the alternation of generations, which phase shows maximum reduction in bryophytes?
Answer: B
In bryophytes, the sporophyte is reduced (2n generation) and dependent on the dominant gametophyte. This reflects their primitive nature in plant evolution.
Q.50Hard
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.51Medium
The microsporophyll in angiosperms is equivalent to which structure?
Answer: C
The stamen is the microsporophyll of angiosperms that bears microsporangia (pollen sacs). Carpels are megasporophylls.
Q.52Easy
Which character would you use to definitively distinguish between a monocot and dicot embryo?
Answer: A
The most definitive character for embryo classification is the number of cotyledons: monocots have one, dicots have two. This is evident even at the embryonic stage.
Q.53Medium
The transition from aquatic to terrestrial life in plants required which critical innovation?
Answer: B
Vascular tissue (xylem and phloem) was essential for water transport in terrestrial environments, enabling plants to grow upright and away from moisture sources.
Q.54Easy
In the angiosperm ovule, the micropyle serves which primary function?
Answer: B
The micropyle is a small opening in the integument through which the pollen tube enters the ovule to reach the embryo sac for fertilization.
Q.55Hard
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.56Easy
Which of the following is NOT a characteristic of monocots?
Answer: D
Monocots have ONE cotyledon, not two. Two cotyledons is a characteristic feature of dicots. Options A, B, and C are all typical monocot features.
Q.57Hard
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.58Easy
Which of the following plant groups shows the most advanced vascular tissue organization?
Answer: C
Gymnosperms possess the most advanced vascular tissue with secondary growth, vessels in some species, and efficient water transport mechanisms compared to other groups.
Q.59Easy
In moss, the dominant generation is the gametophyte. What is the ploidy level of this structure?
Answer: B
The gametophyte generation is always haploid (n) because it develops from spores after meiosis and produces gametes through mitosis.
Q.60Medium
Which character distinguishes Selaginella from Lycopodium among pteridophytes?
Answer: B
Selaginella exhibits heterospory (producing two types of spores) and possesses a ligule (a small appendage), which are absent in Lycopodium.
