DENDROLOGY

Detailed explanation-1: -Archaea are the most extreme of all extremophiles-some kinds live in the frigid environments of Antarctica, others live in the boiling acidic springs of Yellowstone. These single-celled organisms have no nucleus, but have a unique, tough outer cell wall.

Detailed explanation-2: -Euglenophyta, flagellated, mostly unicellular algae that occur often in fresh water. In contrast to most other algae, they lack cell walls and can be mixotrophic (both autotrophic and heterotrophic). An example is Euglena gracilis. Chlorophyta (green algae), mostly unicellular algae found in fresh water.

Detailed explanation-3: -Protozoa: protozoa are unicellular eukaryotes found in soil or water. They vary in shape, size, mode of nutrition, and cellular structure. Protozoa may be found in the body as a part of normal flora or as a source of diseases.