· Most phytoplankton is too small to be individually seen with the unaided eye.
· They live in the upper layers of the ocean and which forms the basis of the marine food chain or web..
· Zooplankton are microscopic animals that eat other plankton.
· Macrophyte is an aquatic plant that grows in or near water and is either emergent, submergent, or floating.
· “A fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins”.
· “Most fish are "cold-blooded", or ectothermic, allowing their body temperatures to vary as ambient temperatures change”.
· Crustaceans are a large group of arthropods.
· They treated as a subphylum.
· Mammals are animals which share a number of important traits that make them different from other animals.