阅读下在文字,按要求答题。国际社会共同抵御禽流感禽流感是禽流行性感冒的简称,被国际兽疫局定为A类传染病,又称真性鸡瘟或欧洲鸡瘟。禽流感病毒属于甲型(A型)流感病毒。病毒外壳有一层棒状和蘑菇状的蛋白质纤突。棒状的红细胞有凝集性,被称为血凝素 (HA),是帮助病毒感染其细菌的酵素,其作用有如病毒的钥匙,用来打开及 Read the text below and answer the questions as required. The international community has jointly resisted bird flu. Bird flu is the abbreviation for avian influenza. It is classified by the OIE as a Class A infectious disease. It is also known as a true chicken gizzard or a European chicken gizzard. Avian influenza viruses belong to influenza A (type A) viruses. The virus shell has a rod-shaped and mushroom-like protein fiber. The rod-shaped red blood cells have agglutinating property, called hemagglutinin (HA), which is an enzyme that helps the virus to infect its bacteria. Its role is like a virus key, used to open and