Reason (R): The anthers contain pollen sacs, where microspores
develop into pollen grains that carry male gametes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pollen grains, produced in the anthers, contain
male gametes. The anther houses pollen sacs, where microspores undergo
development to form pollen grains.
Reason (R): Pollination is essential for fertilization to occur
in plants.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pollination enables fertilization by ensuring the
transfer of male gametes (pollen) to the stigma, where they can travel down to
the ovary for fertilization.
Reason (R): Cross-pollination promotes genetic diversity, which
is crucial for the survival of the species.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cross-pollination between plants of the same
species enhances genetic variation, which aids the adaptation of species to
changing environments.
Reason (R): In self-pollination, pollen from the anther is
transferred to the stigma of the same flower or another flower of the same
plant.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In self-pollination, the pollen from an anther can
fertilize the stigma of the same or another flower on the same plant, making it
possible in both unisexual and bisexual flowers.
Reason (R): The pollen tube carries the male gametes to the
ovule, where fertilization occurs.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In fertilization, the pollen tube grows from the
stigma to the ovule, where it releases male gametes that fuse with the female
gametes (ovule) to form a zygote.
Reason (R): The ovule contains the embryo sac, which after
fertilization, gives rise to the seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the ovule develops into a
seed, containing the zygote that becomes the embryo.
Reason (R): The ovary contains the ovules, which after
fertilization, become seeds.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The ovary houses the ovules, which after
fertilization, become seeds. The ovary itself later transforms into the fruit.
Reason (R): The fertilization of the egg cell in the ovule
gives rise to the embryo.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the egg cell in the ovule
forms an embryo, which grows into a seed.
Reason (R): The fusion of the haploid male and female gametes
during fertilization restores the diploid number of chromosomes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The male and female gametes are haploid, and their
fusion results in a diploid zygote.
Reason (R): The endosperm is formed by the fusion of one male
gamete with the two polar nuclei in the embryo sac.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: During double fertilization, one male gamete fuses
with the egg to form the zygote, while the other fuses with the polar nuclei to
form the endosperm.
Reason (R): The ovule contains the egg cell, which, after
fertilization, develops into the embryo.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The fertilization of the egg cell inside the ovule
results in the formation of an embryo, which grows within the ovule to form a
seed.
Reason (R): The embryo develops from the zygote, formed after
the fusion of male and female gametes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the zygote divides and
develops into an embryo inside the seed.
Reason (R): A bisexual flower contains both male and female
reproductive organs, while unisexual flowers contain only one type of
reproductive organ.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Bisexual flowers have both stamens and pistils,
while unisexual flowers have either stamens or pistils but not both.
Reason (R): Pollination helps the transfer of male gametes
(pollen) from the anther to the stigma of the flower.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pollinators, such as wind, water, and insects,
facilitate the transfer of pollen (male gametes) to the stigma for fertilization
to occur.
Reason (R): Double fertilization involves two fusions – one
between the male gamete and the egg cell, and the other between the male gamete
and the polar nuclei.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Double fertilization in plants results in the
formation of both a zygote (embryo) and endosperm.
Reason (R): Unisexual flowers contain only one type of
reproductive organ, either stamen or pistil.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Papaya has unisexual flowers where male and female
reproductive organs are present in separate flowers.
Reason (R): Self-pollination reduces genetic diversity, which
increases the likelihood of harmful recessive traits being expressed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Self-pollination results in offspring with similar
genetic makeup, which can lead to inbreeding depression due to the expression of
harmful recessive genes.
Reason (R): Cross-pollination brings together gametes from
genetically different plants, which increases variation in the offspring.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cross-pollination promotes genetic diversity,
which is beneficial for the adaptation and survival of plant species.
Reason (R): The ovary contains the ovules, where the female
gametes are produced.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The ovary contains ovules, which produce female
gametes (eggs) for fertilization.
Reason (R): The male gamete must fuse with the female gamete in
the ovule to form a zygote, which later develops into a seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Fertilization leads to the formation of a zygote,
which develops into a seed within the ovule.
Reason (R): The pollen grain contains two male gametes, which
are essential for fertilization.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The pollen grain is the male gametophyte that
contains two male gametes. These gametes are involved in the fertilization
process.
Reason (R): After fertilization, the diploid zygote divides to
form the embryo, which later becomes the seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The zygote formed after fertilization undergoes
mitotic divisions to form an embryo within the seed.
Reason (R): Mitosis increases the number of cells, while
differentiation ensures the specialization of cells to form various plant
tissues.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, mitotic divisions increase
the cell number, while differentiation leads to the formation of specialized
cells and tissues within the embryo.
Reason (R): The endosperm forms by the fusion of one male
gamete with two polar nuclei, providing nourishment to the developing embryo.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The endosperm forms before the embryo during
double fertilization. It nourishes the developing embryo.
Reason (R): Bisexual flowers contain both stamens (male organs)
and pistils (female organs) in the same flower.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Bisexual flowers have both male (stamens) and
female (pistils) reproductive organs within the same flower.
Reason (R): Cross-pollination results in genetically diverse
offspring, enhancing the adaptability of the species.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cross-pollination ensures genetic diversity, which
helps plants adapt to changing environmental conditions.
Reason (R): Double fertilization involves two male gametes: one
fertilizes the egg cell to form the zygote, and the other fertilizes the polar
nuclei to form the endosperm.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In double fertilization, one male gamete fuses
with the egg cell to form a zygote, and the other fuses with the polar nuclei to
form the endosperm.
Reason (R): After fertilization, the ovary wall thickens to
form the fruit, and the ovule develops into a seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the ovary matures into the
fruit, and the ovule becomes a seed.
Reason (R): Pollination is the process of transferring pollen
from the anther to the stigma, enabling fertilization.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pollination is the transfer of pollen, carrying
male gametes, to the stigma, which is essential for fertilization to take place.
Reason (R): Maize has unisexual flowers that rely on wind for
the transfer of pollen from male to female flowers.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In maize, unisexual flowers rely on wind for
pollination as the pollen is lightweight and can travel long distances.
Reason (R): The fertilized ovary transforms into a fruit, while
the ovule becomes the seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the ovary develops into the
fruit, and the ovule forms a seed.
Reason (R): Fertilization involves the fusion of haploid male
and female gametes, resulting in a diploid zygote.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The fusion of haploid gametes restores the diploid
chromosome number, leading to the formation of a diploid zygote.
Reason (R): The anther contains pollen sacs where microspores
develop into male gametes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Male gametes (sperm cells) are produced in the
anther, which contains pollen sacs where microspores develop into pollen grains
carrying the male gametes.
Reason (R): The stored food in the seed helps the embryo grow
when it begins germination.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Seeds contain an embryo, which is nourished by the
stored food in the endosperm or cotyledons during germination.
Reason (R): Parthenocarpy occurs when fruits develop without
fertilization of the ovule, producing seedless fruits.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In parthenocarpic fruits, the ovary develops into
fruit without fertilization, producing seedless fruits.
Reason (R): Cleistogamous flowers do not open, but
self-pollination occurs within the closed flower.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cleistogamous flowers remain closed, and
self-pollination takes place within them, ensuring reproduction without the need
for external pollinators.
Reason (R): Heterostyly promotes cross-pollination by
preventing self-pollination between flowers with different style lengths.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Heterostyly involves flowers with different style
lengths, promoting cross-pollination and preventing self-pollination.
Reason (R): The fertilized ovule contains the zygote, which
eventually develops into an embryo and seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the zygote inside the ovule
develops into an embryo, and the ovule becomes the seed.
Reason (R): The pollen tube provides a pathway for the male
gamete to travel from the stigma to the ovule for fertilization.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The pollen tube transports the male gamete from
the stigma to the ovule, where fertilization occurs.
Reason (R): Dioecy increases cross-pollination by ensuring that
male and female gametes are produced on different plants.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In dioecious plants, male and female flowers are
on separate individuals, encouraging cross-pollination.
Reason (R): The fusion of male and female gametes results in
the formation of a diploid zygote.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Fertilization leads to the fusion of male and
female gametes to form a diploid zygote.
Reason (R): The ovary wall thickens after fertilization to form
the fruit, and the ovule becomes a seed.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the ovary wall thickens and
forms the fruit, while the ovule becomes a seed.
Reason (R): Vegetative propagation involves the growth of new
plants from vegetative parts like roots, stems, or leaves.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vegetative propagation occurs when new plants grow
from parts of the parent plant, bypassing the need for fertilization.
Reason (R): Parthenocarpy allows fruit development without
fertilization, resulting in seedless fruits.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Parthenocarpic fruit development occurs without
fertilization, leading to the formation of seedless fruits.
Reason (R): Monocots have seeds with one cotyledon, and their
ovules have only one integument.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Monocots have ovules with a single integument,
which correlates with their one-cotyledon seed structure.
Reason (R): Only one of the four megaspores survives to develop
into the female gametophyte.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The megaspore mother cell undergoes meiosis,
producing four megaspores, but only one survives to form the female gametophyte.
Reason (R): Wind, water, insects, and birds can all facilitate
the transfer of pollen from one flower to another.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pollination can occur through various agents like
wind, water, insects, or birds, ensuring the transfer of pollen.
Reason (R): Cross-pollination promotes genetic diversity and
can increase a plant's chances of survival.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cross-pollination helps in genetic diversity,
increasing the adaptability and survival of the plant species.
Reason (R): Bisexual flowers contain both stamens (male) and
pistils (female) within the same flower.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Bisexual flowers contain both male (stamens) and
female (pistils) reproductive organs, allowing self-pollination or
cross-pollination.
Reason (R): Fertilization involves the fusion of two haploid
gametes, restoring the diploid number of chromosomes in the zygote.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: During fertilization, the fusion of two haploid
gametes restores the diploid chromosome number in the zygote.