What are the advantages of humans being multicellular and why?

Answer 1

One advantage of an organism being multicellular is that it can grow to a large size. A single cell cannot do this. For one thing, unless it were wafer-thin, it would not have a large enough surface area to supply the needs of its contents: enough oxygen for the mitochondria, enough glucose and amino acids for the cell, and so. Nor would it be able to remove its wastes, like carbon dioxide and urea, fast enough. Another advantage is differentiation. This means that different cells can become specialized for different purposes, and be very efficient at them. Thus some cells specialize in conducting messages, some in carrying oxygen, some in storing lipid (fat) as an energy reserve and, in some animals, for thermal insulation. The entire body is thus like a human community with division of labor.

Answer 2

Humans being multicellular allows for specialization of cells, leading to more efficient functions and processes in the body. It also provides redundancy, as if one type of cell fails, others can compensate. Multicellularity also allows for larger body size, increased complexity, and better adaptability to changing environments.