What is a common characteristic of benthic macroinvertebrates?

Benthic macroinvertebrates are organisms that live at the bottom of water bodies, such as rivers, lakes, and ponds, and are large enough to be seen without the need for a microscope. This visibility allows researchers and scientists to identify and study these organisms easily when assessing water quality and ecosystem health. These creatures play critical roles in the aquatic ecosystem, including serving as indicators of environmental conditions and forming an important part of the food web.

The other options do not accurately describe benthic macroinvertebrates. For instance, they are not characterized by being active swimmers since many are either sessile or move along the substrate rather than swimming freely. Additionally, they can be found in both freshwater and saltwater environments. Lastly, they are not planktonic organisms; rather, they are typically found attached to surfaces or buried in sediment rather than drifting in the water column.