Because humans eat both plants and meat
The early hominid stages can be differentiated from one another based on the complexity of the tools used by these species. The tool evolved along with the evolution of the humans. The more the hominids evolved by more complex their tools became. The tools made by the earliest hominids were used to fish out the termites. These tool developed and became more widely used as the humans evolved.
Hence, the answer is 'by observing the complexity of the tools'.
Endoplasmic Reticulum is a long piece of membrane inside of the cytoplasm in a Eukaryotic cell. It connects to the Nuclear Membrane as well. It has numerous ribosomes attached as it helps with protein and lipid synthesis. It has both smooth and rough forms, each which do different things inside the cell.
