Question

the theory of spontaneous generation proposed that life could spontaneously arise from nonliving things. it explained observations like the appearance of maggots on dead flesh and frogs emerging from mud. what new evidence led to the replacement of the theory of spontaneous generation? the discovery of the cell and that cells come from pre - existing cells. the discovery of the atom and development of atomic theory. the discovery of the gene and the process of genetic inheritance. the discovery of common ancestry and the theory of evolution.

Explanation:

The theory of spontaneous generation was replaced when the cell theory (that cells come from pre - existing cells) was established. This is because the idea that life can only come from pre - existing life (cells) contradicts the idea of spontaneous generation (life from non - living matter). The discovery of the atom and atomic theory is about matter's structure, genetics is about inheritance, and evolution is about common ancestry, none of which directly relate to disproving spontaneous generation like the cell theory does.

Answer:

A. The discovery of the cell and that cells come from pre - existing cells.