There are different biomes because of climate.
The correct answer is that different genes are expressed in different cells.
The cellular differentiation is the process in developmental biology where a cell modifies from one kind of cell to another. Most generally the cells are modified to a more specialized kind. Differentiation takes place various times at the time of development of a multicellular species as it modifies from a basic zygote to a composite system of tissues and kinds of cells.
The correct answer is A. Spontaneous generation does not happen.
He wanted to show that cells always come from other cells, meaning that cells and life organisms cannot come from non-matter or dead matter. Meaning that maggots in rotting bodies are not made from the bodies.
The answer is the nervous system.
Hope this helps!