In the corn cob, the tassels (ears) that wave in the wind represent:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Stigma and style
Explanation: In a corn cob, the ears or tassels seen waving in the wind are nothing but the stigma and style which wave in the wind to trap pollen grains.
Which of the following is a fresh water plant pollinated by water?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Vallisneria
Explanation: Some examples of water pollinated plants are Vallisneria and Hydrilla which grow in fresh water. Zostera is a marine seagrass.
How does pollination occur in Water Hyacinth and Water Lily?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: By insects or wind
Explanation: In a majority of aquatic plants such as water hyacinth and water lily, the flowers emerge above the level of water and are pollinated by insects or wind as in most land plants.
In seagrasses like Zostera, the pollen grains are:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Ribbon like and long
Explanation: Pollen grains in many such species (seagrasses) are long, ribbon like and they are carried passively inside the water.
The tallest flower, Amorphophallus, provides which reward to its pollinator?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Safe place to lay eggs
Explanation: In some species floral rewards are in providing safe places to lay eggs; an example is that of the tallest flower of Amorphophallus.
Which moth species has an obligate relationship with the plant Yucca?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Yucca moth
Explanation: A relationship exists between a species of moth and the plant Yucca where both species cannot complete their life cycles without each other. The moth deposits eggs in the locule of the ovary.
Continued self-pollination in flowering plants results in:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Inbreeding depression
Explanation: Continued self-pollination results in inbreeding depression. Plants have developed devices to discourage self-pollination.
Which condition prevents both autogamy and geitonogamy?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Dioecy
Explanation: In several species such as papaya, male and female flowers are present on different plants (dioecy). This condition prevents both autogamy and geitonogamy.
What is the ploidy of the Primary Endosperm Nucleus (PEN)?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Triploid (3n)
Explanation: The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN).
The fusion of three haploid nuclei in the embryo sac is termed:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Triple fusion
Explanation: Since this process involves the fusion of three haploid nuclei (one male gamete and two polar nuclei), it is termed triple fusion.