Have the animals and plants, such as lichen, come to existance from symbiosis between simple animates?

Question

The body structure of most of the animals and plants, such as lichen, have come to existance from symbiosis between simple animates.
http://www.geocities.com/ramin1102000/book2.html

Answer 1

I don't understand what you are asking. I followed the link in your question and it took me to a book that you wrote, I think.

Lichens are neither animals nor plants. Lichens are composed of a fungus and an alga living together in a mutualistic relationship - a relationship that is good for both species.

Many researchers believe that animals had single-celled heterotrophic ancestors, possibly similar to protozoa. Most believe that green algae are the ancestors of today's plants.