The lowest level of organization in living organisms is

1. Analyze the question The question asks for the lowest level of organization in living organisms. The options are all levels of biological organization, so we need to rank them from simplest to most complex.

2. Explain the concept Living things are organized in a hierarchy, from simple to complex:

Cell → Tissue → Organ → System → Organism

• Cell: the basic structural and functional unit of life
• Tissue: a group of similar cells doing the same job (e.g., muscle tissue)
• Organ: different tissues working together (e.g., the heart)
• System: several organs working together (e.g., the circulatory system)

(Strictly speaking, organelles and molecules exist inside cells, but among the options given, the cell is the lowest level that is considered "living.")

3. Step-by-step solution

• Organ is made of tissues, so it is higher than tissue.
• System is made of organs, so it is higher than organ.
• Tissue is made of cells, so it is higher than cell.
• Cell is not made up of any of the other listed options. It is the smallest and simplest unit.

4. Answer The correct option is B. cell.

5. Exam tip Remember the order with: Cells Take Over Space → Cell, Tissue, Organ, System. Whenever a question asks for the "lowest" level, start from the cell and move up. For "highest," go to the organism.