There are different organisms. Some of them are multi cellular and some of them are uni cellular. The process carried out by a group of cells in multi cellular organisms are carried out by one single cell in uni cellular organisms. How is this possible?
What is the term used for the role played by the organisms in their environment?
According to Lamarck : changes in the environment influence changes in the use and disuse of a body part of an organ, so there are vestigal organs like appendix, etc in humans also, so is it right to think that these organs were used by earlier humans that evolved on the earth but after some time their use become less which eventually made them vestigal?