Question

a virus that causes intestinal dysfunction cannot attack respiratory cells because - it has no method to enter the respiratory system. the respiratory tract is protected by a mucus membrane. proteins on the virus do not recognize the respiratory cell. respiratory cells are equipped to destroy all entering viruses.

Explanation:

Viruses attach to specific host - cells via surface proteins. If the proteins on a virus that targets intestinal cells do not recognize the receptors on respiratory cells, it cannot attack them. The mucus membrane may not completely prevent virus entry, respiratory cells cannot destroy all entering viruses, and the virus may have a way to enter the respiratory system but lacks the proper recognition.

Answer:

proteins on the virus do not recognize the respiratory cell.