Which is not a main feature of the cell theory

Each and every cell is encircled by a membrane. this is not a mean feature of a cell theory.

Explanation:

All living organisms are composed of cells. They may unicellular like bacteria, fungi and protista and multicellular like plants, animals etc.

A cell is basic unit of life as gene is a basic unit of heredity. According to cell theory cells are arise from a pre-existing cells. The two kinds of cells are Eukaryotic cell with a definite nucleu