Now that we know about both prokaryotic and eukaryotic cells, let's look at the endosymbiosis theory. This theory suggests that mitochondria and plastids in eukaryotic cells were once independent prokaryotic cells.
Avian influenza (AI) is an infectious viral disease of birds (especially wild water fowl such as ducks and geese), often causing no apparent signs of illness. AI viruses can sometimes spread to domestic poultry and cause large-scale outbreaks of serious disease.
About the Flu Virus. Influenza, or flu, is a respiratory infection caused by any of several flu viruses, which are classified as type A, B, or C based on their nucleic acids and protein composition. Type A viruses are found in humans and many animals, including ducks, chickens, pigs, and whales.