Biotechniciansâ?? work focuses on the study of living organisms. They conduct research and do experiments to help them discover new pharmaceuticals and medical treatments, improve agricultural productivity, advance forensic processes and develop new technologies.
By single organisms I assume you mean unicellular organisms. That is one of the more well accepted theories involving the origin of multicellular organisms. It is, however, far being definitively proven.
1. Organisms reproduce. 2. Organisms respond. 3. Organisms have one or more skin cells. 4. Organisms develop. 5. Organisms have a heart. No, they don't. At least, not all of them. This is the most common mistake that people make.
A marine biologist works to determine how marine life organisms get food, reproduce, develop, why certain groups of organisms live in certain parts of the ocean, and how they interact with other organisms in the ocean.