What best characterizes lotic systems?

Lotic systems are best characterized by the presence of flowing water bodies, which is why the correct answer focuses on this aspect. These systems include rivers, streams, and creeks where water moves continuously in one direction. This flowing water is crucial for the ecosystem, as it influences the physical and chemical characteristics of the environment, supporting diverse habitats and aquatic life.

The movement of water in lotic systems plays a vital role in oxygenation, nutrient transport, and sediment distribution, which are essential for maintaining healthy ecosystems. Organisms that inhabit lotic environments are often adapted to the flow, exhibiting traits that help them survive in currents, such as streamlined bodies or strong anchoring mechanisms.

In contrast, stagnant water is characteristic of lentic systems, which include lakes and ponds where water is still. A lack of outflow is also a feature of certain lentic systems, but not of lotic ones, as flowing water naturally exits the system. Additionally, large depressions may hold standing water but do not define the flowing nature found in lotic systems. Thus, the defining trait of lotic systems is indeed their flowing water bodies.