The cell is the basic structural and functional unit of________.

Hint: Omnis cellula e cellula means the new cells arising from the pre-existing cells. A cell can divide independently. Each organism is made up of a cell. Tissues are formed by a group of cells. So each cell has regeneration capacity from its own through the cell division.

Complete answer:
The cell is defined as the basic structural, functional and biological unit of all the known living organisms. A cell is also said to be the smallest unit of life. 'Building blocks of life' is often called a cell. The study of the cell is known as ‘Cell Biology’; ‘Cellular biology’ or ‘cytology’.
A cell consists of cytoplasm covered within a membrane, which contains many biomolecules such as proteins and nucleic acids. Most animal and plant cells are seen only under the microscope with 1-100mm dimensions. Organisms can be differentiated as unicellular or multicellular. Most unicellular are considered as microorganisms as they are small and made up of a single cell. The number of cells in plants and animals varies from species to species, it has been estimated that humans contain somewhere around cells. The human brain has around 80 billion of these cells.
Cell theory was first developed by Matthias Jakob Schleiden and Theodor Schwann, stating that all the organisms are composed of one or more cells, those cells are the fundamental unit of structure and function in all living organisms, and also that the cells come from pre-existing cells. Cells emerged on earth approx. 3.5 billion years ago.

Hence, life is the correct answer.

Note:
Cells were discovered by Robert Hooke in 1665 in cork, who named them for their resemblance to cells inhabited by Christian monks in a monastery. In 1838 Matthias Schleiden (botanist) and 1839 Theodore Schwann (zoologist) both concluded that the cell wall is the unique character of plant cells.