Final answer:
The presence of blood in the stool of a patient with diarrhea can be caused by loss of protein or infections like EHEC or Shigella.
Step-by-step explanation:
The presence of blood in the stool of a patient with diarrhea is the result of multiple factors. It can be caused by loss of protein, as proteins play a role in maintaining the integrity of the intestinal lining. Additionally, certain infections, such as EHEC infection and Shigella infection, can also lead to bloody stools.
EHEC (Enterohemorrhagic Escherichia coli) infection can cause bloody diarrhea, severe cramping, and no fever. Shigella infection can cause dysentery, which is characterized by bloody stools, cramps, and fever. Therefore, the correct answer is 4) All of these.