What is the primary mode of pollination in Vallisneria and Hydrilla?

Hydrophily (water pollination)

The correct answer is Option (3)- Hydrophily (water pollination)

The plants use two abiotic (non-living) agents and one biotic (living) agent for pollination. The abiotic agents are wind and water, while the biotic agent mentioned is animals. Fungi are not listed as a possible external agent for pollination.

Wind pollination, also known as anemophily, occurs when pollen grains are carried by the wind from the anthers of one flower to the stigma of another flower. This type of pollination is common in plants with small, light pollen grains that are easily carried by air currents. Examples of wind-pollinated plants include grasses, many trees (such as conifers), and some cereal crops.

Water pollination, or hydrophily, Pollination by water is quite rare in flowering plants and is limited to about 30 genera, mostly monocotyledons. Some examples of water-pollinated plants are Vallisneria and Hydrilla which grow in fresh water and several marine sea-grasses such as Zostera. Water-pollinated flowers are not very colourful and do not produce nectar.

Insect pollination, or entomophily, involves the transfer of pollen grains by insects such as bees, butterflies. Flowers that rely on insect pollinators often have bright colors, attractive scents, and nectar rewards to attract the insects. The insects inadvertently pick up pollen on their bodies as they move from flower to flower, and when they visit another flower of the same plant species, the pollen can be transferred to the stigma.

Zoophily is a type of pollination where animals (such as insects, birds, bats, and other creatures) act as pollinators, transferring pollen from the anther to the stigma of flowers. It is a highly efficient and common method of pollination in flowering plants.