From left to right, the model begins with two virus structur…
From left to right, the model begins with two virus structures. The structure on top is an Avian Influenza Virus, with the R N A Molecules and Glycoprotein X labeled. The bottom structure is a Human Influenza Virus, with the R N A Molecules and Glycoprotein Y labeled. A right-facing arrow points from each virus to a Pig Respiratory Tract Cell with D N A Molecules labeled. A right-facing arrow points from the Pig Respiratory Tract Cell to a New Strain of Human Influenza Virus, with the R N A Molecules and Glycoprotein Z labeled. The cells lining the respiratory tract of pigs have receptors for both avian and human influenza viruses. Based on the model above, which of the following best describes the origin of the new strain of human influenza virus?