Which aspects of cell structure best reveal evolutionary unity? what are some examples of specialized mods?

1. The genetic material is a good evidence of evolution because it's been conserved through time but with some slight differences.
Another important aspect is the mitochondria. The mitochondria resulted from a symbiotic relationship between bacteria and pre-eukaryotes. Explaining why the mitochondria looks like a bacteria and has bacterial DNA. 

2.  specialized cellular modifications:

There are cellular modifications happening in multicellular organisms. That means, they have different types of cells, with different functions and will express different characteristics. For example:
- Nerve cells have  dendrites  which is important to receive the electrical signal from another neuron, other cells don't have that.
- Sperm cells have a tail ( flagellum) in order to swim through the vagina and no other cell has that.

To kill bacteria from our body especially from stomach