Hint: The plants have specific modifications to survive in the environment they are living. They show stem, roots and leaves modifications. The submerged hydrophytes can be floating or submerged in water. The leaves of these plants are dissected in many parts to resist the water currents.
The submerged hydrophytes are the plants which grow below the water surface and are not in contact with the atmosphere. They can be free floating or rooted in the surface.
The submerged leaves are dissected or divided. It plays an important role in creating a very large surface area for absorption and photosynthesis. It also protects the leaves of the plants from the moving water (currents and waves). It prevents the tearing of the leaves. The heavy waves can be damaging to the leaves of the plant. It also minimizes the water resistance.
Examples of submerged plants are vallisneria, Hydrilla, Potamogetan, najas, etc. Some of the plants such as anacharis are the key oxygenators of the hydrophytes plants. They help to remove the carbon dioxide and add oxygen to the water. They are good submerged plants.
From the above information we have found that dissected leaves help to increase surface area and reduce the effect of water currents.
Hence, the correct answer is option (D).
Note: The hydro-phytic plants are mainly of four types: emergent, floating, and sub-merged and algae. The algae grow the water bodies due to the presence of the floating and emergent plants. They block the sunlight. The submerged plants help to consume the waste nutrients that are used by algae. The totally submerged plants are true water plants. They do not have stomata in their leaves.