Which term best describes an organism that is unable to move independently?

The term "sessile" is used to describe organisms that are fixed in one place and unable to move independently. This term is commonly applied to various types of organisms, such as certain types of plants, corals, and barnacles, which are anchored to a substrate or surface. Sessile organisms often rely on water currents or other means to bring food and nutrients to them, rather than actively seeking it out.

In contrast, organisms classified as motile or mobile have the ability to move freely and independently in their environment. The term "floating" refers to organisms that may be carried by currents but are generally not fixed to a surface; they can still exhibit some degree of movement. Understanding these terms is crucial in biology, especially when studying ecology and the behaviors of different organisms within their habitats.