The answer to your question is Mutualism.
Plant cell have cell wall and animals cell don’t have
Plant cell have plastids and animal cell don’t have
The buffer systems functioning in blood plasma include plasma proteins, phosphate, and bicarbonate and carbonic acid buffers. The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range.
ITS FLAGELLA THEY ARE FOUND IN ALL 3 KINGDOMS OF CELLS