What is the fundamental principle described by the cell theory?

• A. Cells are only found in multicellular organisms
• B. All living organisms are composed of cells
• C. Cells can arise from non-living matter
• D. Cells exist only in specific environments

Answer: (B)

The fundamental principle described by the cell theory is that all living organisms are composed of cells. This principle highlights the basic unit of life and emphasizes that whether an organism is unicellular or multicellular, it is fundamentally made up of cells. This foundational concept in biology underscores the importance of cells as the building blocks of all living things, providing a common link among the diverse forms of life on Earth.

Understanding that living organisms are made up of cells is critical for studying physiology and biology, as it leads to the exploration of how cells function, interact, and sustain life. Other statements, such as cells being exclusive to multicellular organisms or arising from non-living matter, do not align with the established principles of cell theory and modern understanding of biology.