Which of the following factors is essential for the survival of aquatic weeds?

The essential factor for the survival of aquatic weeds is the availability of nutrients and light. Aquatic plants, including weeds, require specific amounts of light and essential nutrients, such as nitrogen, phosphorus, and potassium, to grow and thrive. These nutrients support photosynthesis, which is critical for the energy production of the plants. Moreover, adequate light is necessary for photosynthesis to occur effectively.

In aquatic environments, the dynamics of light penetration can vary significantly due to water depth, turbidity, and the presence of other organisms, which can impact the growth and survival of aquatic weeds. When both nutrients and light are abundant, aquatic weeds can proliferate rapidly, leading to potential ecological imbalances, such as decreased oxygen levels and habitat disruption for native species.

Factors like predators, competition from other plants, and water temperature may influence the ecosystem dynamics, but they do not directly pertain to the fundamental needs of aquatic weeds for basic growth and survival.