Angiosperm Classification Practice Questions
19 free Angiosperm Classification practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Unlike gymnosperms, the ovules in angiosperms are developed inside specialized structures called:
- A Ovaries
- B Anthers
- C Nucellus
- D Strobili
Correct answer: Ovaries
In angiosperms, the seeds are enclosed within fruits because the ovules develop inside the ovary. This is the primary morphological distinction from gymnosperms, where seeds are naked.
Which of the following is considered the smallest angiosperm?
- A Wolffia
- B Lemna
- C Hydrilla
- D Rafflesia
Correct answer: Wolffia
Wolffia is a microscopic flowering plant, often measuring less than 1 mm. It represents the smallest end of the size spectrum in the diverse Kingdom Plantae.
Angiosperms are classified into two main classes based on the number of:
- A Petals in the flower
- B Carpels in the ovary
- C Vascular bundles in the stem
- D Cotyledons in the seeds
Correct answer: Cotyledons in the seeds
The classification of angiosperms into two main classes is primarily based on whether the embryo within the seed has one cotyledon (monocot) or two cotyledons (dicot).
Which of the following characteristics is typically associated with dicotyledonous plants?
- A Parallel venation in leaf lamina
- B Adventitious root formation
- C Flowers in trimerous whorls
- D Reticulate venation in leaves
Correct answer: Reticulate venation in leaves
Dicotyledons are characterized by seeds with two cotyledons, reticulate (net-like) venation in their leaves, and tetramerous or pentamerous flowers. Monocotyledons typically show parallel venation.
In angiosperms, the male sex organ in a flower is the:
- A Stamen
- B Pistil
- C Sepal
- D Receptacle
Correct answer: Stamen
The stamen is the male reproductive part, consisting of a slender filament and an anther at the tip. Within the anthers, pollen grains are produced following meiosis.
The female sex organ in an angiosperm flower is the pistil, which consists of:
- A Stigma, style, and ovary
- B Anther and filament
- C Petals and sepals
- D Cotyledons and endosperm
Correct answer: Stigma, style, and ovary
The pistil (or carpel) is the female reproductive unit. It is composed of a basal swollen ovary, an elongated style, and a receptive tip called the stigma.
Within an angiosperm ovule, the highly reduced female gametophyte is known as the:
- A Embryo sac
- B Pollen grain
- C Nucellus
- D Endosperm
Correct answer: Embryo sac
Each ovule contains a female gametophyte called the embryo sac. It is formed through meiosis and usually consists of a seven-celled, eight-nucleate structure.
A typical mature embryo sac of an angiosperm contains how many cells and nuclei?
- A 3 cells and 3 nuclei
- B 8 cells and 8 nuclei
- C 5 cells and 7 nuclei
- D 7 cells and 8 nuclei
Correct answer: 7 cells and 8 nuclei
The mature embryo sac is a 7-celled structure containing 8 nuclei. These include one egg cell, two synergids, three antipodal cells, and one large central cell with two polar nuclei.
The process where one male gamete fuses with the egg cell and the other fuses with the diploid secondary nucleus is called:
- A Double fertilization
- B Syngamy
- C Triple fusion
- D Porogamous fertilization
Correct answer: Double fertilization
Double fertilization is a unique event in angiosperms. It involves syngamy (fusion of sperm and egg) and triple fusion (fusion of sperm with the two polar nuclei).
What is the result of the 'triple fusion' event in angiosperms?
- A Primary Endosperm Nucleus
- B Diploid zygote
- C Degenerated antipodal cells
- D Mature seed coat
Correct answer: Primary Endosperm Nucleus
Triple fusion involves the fusion of the second male gamete with the diploid secondary nucleus (formed by two polar nuclei). This results in a triploid (3n) Primary Endosperm Nucleus.
In angiosperms, the Primary Endosperm Nucleus (PEN) eventually develops into the:
- A Embryo
- B Seed coat
- C Endosperm
- D Pericarp
Correct answer: Endosperm
The triploid PEN develops into the endosperm, which serves as a nutrient-rich tissue. It provides nourishment to the developing embryo during seed maturation.
Which structure in the embryo sac degenerates after fertilization?
- A Zygote
- B Primary endosperm nucleus
- C Synergids and antipodals
- D Central cell
Correct answer: Synergids and antipodals
After double fertilization, the synergids and antipodal cells serve no further purpose and typically degenerate. Only the zygote and the primary endosperm nucleus continue to develop.
Monocotyledons are distinguished by flowers that are usually:
- A Tetramerous
- B Pentamerous
- C Trimerous
- D Apetalous
Correct answer: Trimerous
Monocot flowers are typically trimerous, meaning their floral parts (petals, sepals, stamens) are in multiples of three. Dicots usually have floral parts in multiples of four or five.
What happens to the ovary after the fertilization process in angiosperms?
- A It gradually withers and falls off
- B It develops into the seed
- C It develops into the fruit
- D It remains unchanged
Correct answer: It develops into the fruit
Following fertilization, the ovules develop into seeds while the surrounding ovary matures and ripens into a fruit. This protection and dispersal mechanism is key to angiosperm success.
Which of the following plants is an example of a monocotyledon?
- A Mango
- B Sunflower
- C Maize
- D Pea
Correct answer: Maize
Maize (corn) is a monocotyledon characterized by parallel venation and a single cotyledon in its seed. Mango, sunflower, and pea are all examples of dicotyledonous plants.
The pollen grains are dispersed from the anthers and carried by which agents in angiosperms?
- A Wind and water as the main dispersal agents
- B Insects and animal pollinators
- C Wind, water, and various biotic agents
- D Self-propulsion and mechanical release
Correct answer: Wind, water, and various biotic agents
Angiosperms utilize a wide array of pollination vectors, including wind, water, and many animals like insects, birds, and bats. This diversity in pollination agents has contributed to their vast evolutionary radiation.
The zygote in angiosperms develops into the:
- A Endosperm
- B Embryo
- C Seed coat
- D Ovule
Correct answer: Embryo
The zygote is the diploid cell resulting from syngamy. It undergoes multiple rounds of mitosis and differentiation to form the embryo, which contains the future root and shoot systems.
Which of the following is a characteristic of Eucalyptus among angiosperms?
- A It is a parasitic plant that lacks chlorophyll
- B It is one of the tallest flowering plants
- C It lacks vascular tissue in its stems
- D It produces naked seeds without ovaries
Correct answer: It is one of the tallest flowering plants
Eucalyptus species are among the tallest trees in the world, some reaching over 100 meters in height. This demonstrates the structural efficiency of angiosperm vascular systems.
The primary role of the stigma in the angiosperm reproduction is to:
- A Produce ovules for fertilization
- B Receive pollen grains for germination
- C Protect the developing embryo from damage
- D Nourish the growing pollen tube
Correct answer: Receive pollen grains for germination
The stigma is the uppermost part of the pistil, often sticky or feathery. Its function is to receive pollen grains and provide the necessary environment for them to germinate and grow a pollen tube toward the ovule.