Q41. Which of the following pteridophytes is heterosporous?
[A] Dryopteris
[B] Pteris
[C] Selaginella
[D] Adiantum
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Correct Answer: [C] Selaginella
Explanation: Selaginella is a heterosporous pteridophyte, meaning it produces two types of spores: microspores (which develop into male gametophytes) and megaspores (which develop into female gametophytes).
Q42. The development of the zygote into the embryo within the female gametophyte is a precursor to the:
[A] Formation of spores
[B] Development of vascular tissues
[C] Seed habit
[D] Alternation of generations
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Correct Answer: [C] Seed habit
Explanation: Heterospory in pteridophytes, along with the retention of the megaspore within the megasporangium and the development of the zygote into the embryo within the female gametophyte, are important steps in the evolution towards the seed habit seen in gymnosperms and angiosperms.
Q43. Which of the following is a gymnosperm?
[A] Funaria
[B] Marchantia
[C] Pinus
[D] Selaginella
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Correct Answer: [C] Pinus
Explanation: Pinus is a well-known example of a gymnosperm. Other examples include Cycas, Ginkgo, and Gnetum. Funaria and Marchantia are bryophytes, and Selaginella is a pteridophyte.
Q44. The ovules of gymnosperms are:
[A] Enclosed within an ovary
[B] Naked and not enclosed by any ovary wall
[C] Found within fruits
[D] Part of the gametophyte
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Correct Answer: [B] Naked and not enclosed by any ovary wall
Explanation: A defining characteristic of gymnosperms is that their ovules are not enclosed within an ovary wall. After fertilization, the ovules develop into seeds that are also naked, meaning they are not enclosed within a fruit.
Q45. In gymnosperms, the megasporophylls are organized in spirally arranged structures called:
[A] Cones
[B] Flowers
[C] Fruits
[D] Sori
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Correct Answer: [A] Cones
Explanation: In gymnosperms, the megasporophylls (leaves bearing megasporangi[A] are often organized in spirally arranged structures called cones or strobili. These are typically larger than the male cones.
Q46. The female gametophyte in gymnosperms is retained within the:
[A] Anther
[B] Ovary
[C] Megasporangium
[D] Microsporangium
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Correct Answer: [C] Megasporangium
Explanation: In gymnosperms, the female gametophyte develops within the megasporangium (nucellus) and is retained there. This is where fertilization by the male gamete occurs.
Q47. Pollination in gymnosperms occurs through:
[A] Water
[B] Insects
[C] Wind
[D] Animals
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Correct Answer: [C] Wind
Explanation: Pollination in most gymnosperms is anemophilous, meaning it occurs through wind. The pollen grains are released from the male cones and carried by the wind to the female cones, where they reach the ovules.
Q48. The seeds of gymnosperms are:
[A] Enclosed within fruits
[B] Naked
[C] Small and non-viable
[D] Always non-motile
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Correct Answer: [B] Naked
Explanation: As the name suggests (“gymnos” means naked, “sperma” means see[D], the seeds of gymnosperms are not enclosed within a fruit. They develop from the ovules after fertilization and are exposed.
Q49. Which of the following gymnosperms is known for its living fossil status?
[A] Pinus
[B] Cycas
[C] Ginkgo biloba
[D] Cedrus
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Correct Answer: [C] Ginkgo biloba
Explanation: Ginkgo biloba, also known as the maidenhair tree, is often referred to as a living fossil because it is the only surviving species of an ancient group of plants that existed millions of years ago and has remained relatively unchanged.
Q50. Which of the following is the largest group in the plant kingdom?
[A] Algae
[B] Bryophytes
[C] Gymnosperms
[D] Angiosperms
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Correct Answer: [D] Angiosperms
Explanation: Angiosperms, or flowering plants, are the largest and most diverse group in the plant kingdom, comprising over 300,000 known species. They are found in a wide range of habitats and exhibit great diversity in form and structure.