Which statement is one of the three parts of cell theory

First cell theory

All living things are composed of cells

Second cell theory

Cells are the basic unit of structure and function in living things

Third cell theory

All cells are produced from other cells

Therefore, I believe the correct answer would be choice A.

I hope this helps you and have a great day!! :)

The correct answer will be option-A.

Explanation:

Cell theory was proposed by the Schleiden and Schwann in 1839 when they both observed that both plants and animals are made up of structure that contains a nucleus.

They concluded and suggested that all living organism is made up of the smallest nit called cells and cell is the structural and fundamental unit of life.

In the given question, the option which states the cell theory is option-A (statement-1) and therefore is the correct answer.

i am going to guess that it is co2.