GENERAL HISTOLOGY

Detailed explanation-1: -Answer: In the example of corals, the host animal is a multicellular cnidarian, and the endosymbiont is a unicellular alga called a dinoflagellate. The host animal serves as a protected environment, providing the alga with a constant supply of nutrients in the form of nitrogen, phosphorus, and sulfur.

Detailed explanation-2: -The theory of how mitochondria, chloroplasts and other membrane-bound organelles in eukaryotic cell likely arose from a symbiosis between aerobic prokaryotes and host anaerobic eukaryotic ancestors. Developed by Lynn Margulis.

Detailed explanation-3: -The endosymbiotic theory posits that some eukaryotic cell organelles, such as mitochondria and plastids, evolved from free-living prokaryotes. Available data indicate that the mitochondrial endosymbiosis initiated the evolution of the eukaryotic cell, as suggested by Margulis.