Genes are instructions written in code from:

The correct answer is option A, cells come from pre-existing cells.

There are three major concepts of the cell theory and these are as follows:

1) There are numerous cells in an organism. Thus, it can be stated that all organisms  are made of one or more cells.  

2) Each cell has a specific job or function.

3) All cells evolve from their parent cell ( or already existing cells)

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