What is the basic structural unit of all living organisms? 

The cell is the fundamental unit of life and the smallest structure that can carry out all the functions essential for life in living organisms. It is the basic building block of all living organisms and can exist as an independent entity or as part of a multicellular organism. Cells perform a range of functions, including nutrient uptake, energy production, waste elimination, and reproduction. They come in various shapes and sizes, with different structures and functions depending on their specialized roles in specific tissues and organs. Therefore, the cell is the basic structural unit of all living organisms.