The cell is the basic structural and living unit of the living. A cell can exist in isolation and independently. All organisms are composed of cells in which metabolic reactions occur. Cell level.
The level of organization of protozoa coincides with the organismal level. The zygote of a multicellular organism is one cell, but an organismic level.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.