Question

A student made a model of a river in a sandbox. A large pile of sand represents soil and bits of rock in the riverbed. Water pouring from a hose represents river water as it flows downhill. One limitation of the model is that it does not represent how living things affect the flow of water. Which way in refining the model would best address this limitation?

1) Adding plants and animals to the model
2) Increasing the amount of sand in the riverbed
3) Using a larger sandbox for the model
4) Changing the source of the water

Answer 1

To refine a river model and account for the influence of living organisms on water flow, the student should add plants and animals to the model, providing a more complete representation of a river ecosystem.

Step-by-step explanation:

The student's question involves refining a model of a river in a sandbox to better represent how living things affect the flow of water.

To best address the limitation of the model not representing the impact of living organisms on river flow, the most appropriate modification would be: 1) Adding plants and animals to the model. This addition will help the model more accurately reflect the biological elements of a river ecosystem. For example, plants, such as algae, can grow on rocks and affect the clarity of the water and contribute to photosynthesis

Decomposing leaves from bordering trees provide organic material and nutrients, supporting a food chain within the river. Animals, like leeches with their bodies adapted to fast-moving water and trout as important predators, play crucial roles in the dynamics of the river system.

By introducing these biotic factors to the model, the interactions between the living organisms and the physical environment can be examined, leading to a more comprehensive understanding of river ecosystems.