AP BIOLOGY

Detailed explanation-1: -The key difference between the littoral zone and the limnetic zone is the presence of rooted plant growth. The floor under the limnetic zone cannot sustain plant growth due to a lack of sunlight for photosynthesis.

Detailed explanation-2: -In the littoral zone, there is enough light for rooted plants to grow, but beyond this zone, there are no rooted plants as the water is too deep for light to reach them. The deepest part of the open water forms profoundal zone, but this is relevant only in extremely deep lakes.

Detailed explanation-3: -The limnetic zone is well-lighted (like the littoral zone) and is dominated by plankton, both phytoplankton and zooplankton. Plankton are small organisms that play a crucial role in the food chain. Without aquatic plankton, there would be few living organisms in the world, and certainly no humans.

Detailed explanation-4: -The limnetic zone is the open water area where light does not generally penetrate all the way to the bottom. The bottom sediment, known as the benthic zone, has a surface layer abundant with organisms.