Nucleolus - ribosomes are made here
Answer:
Cell is the structural and functional unit of life.
Explanation:
The organisms are classified on the different characteristics basis on the similarities and differences among the organisms. On the cellular basis two main types of organism are unicellular organism and multi cellular organism.
The cell theory of the life was given by Schleiden and Schwann. The cell acts as the basic unit of life as all living organisms are made of the cell. The cell combine together to form tissue, tissue to form organs and organ system as given in the example of the cat.
Oxygen cycle The cycling of oxygen between the biotic and abiotic components of the environment (see biogeochemical cycle). ... In the process of respiration oxygen is taken in by living organisms and released into the atmosphere, combined with carbon, in the form of carbon dioxide.