The answer is operon. These set of genes are transcribed together because they share a single promoter and operator. Therefore they are transcribed into one mRNA and translated together. These genes are, therefore, expressed together at all times. Examples are the tryptophan and lac operons of Escherichia coli
Bacteria is named based on their basic shapes
The skull size of each species!
It's the size of the skull specifically the jaw bones, that can help determine relationships of two hominid species.
Hope this helps!
The answer to this is all of the above.