Answer: The correct answer is -
A. Cells are the basic unit of life.
Explanation:
According to the cell theory of Schleiden and Schwann, which was given in 1838-
Cells are considered to be the basic, structural and functional unit of all life forms.
In other words, cells are considered as the building blocks of life, which make it complex or allows the complexity (such as in case of multicellular organisms) in organisms.
Thus, option A) is the right answer.
