How can organic matter be removed from an ecosystem?

The correct choice highlights the role of water movement in the removal of organic matter from an ecosystem. When organic material, such as leaves, dead plants, or animal waste, is present in an ecosystem, it can be transported away by surface water flow, such as rivers and streams, as well as through groundwater movement. This process not only carries away organic matter but also influences nutrient cycling and ecosystem dynamics, as nutrients from the organic material can be redistributed to other areas, impacting the ecological balance.

In contrast, predator activity primarily influences populations of organisms rather than directly removing organic matter from the ecosystem. Decomposition is essential for breaking down organic matter, but it does not remove it from the ecosystem; rather, it transforms it into simpler substances that can be absorbed by plants or returned to the soil. Photosynthesis serves an entirely different function altogether, converting carbon dioxide and water into glucose and oxygen, thus contributing to the growth of organic matter rather than its removal.