Thu mo vit co nhung dac diem giong vit nhu chan co mang boi, mo vit, de trung nhung khong duoc xep vao lop chim. vay thu mo vit co nhung dac diem co ban nao de duoc xep vao lop chim. vay thu mo vit co nhung dac diem co ban nao de duoc xep vao lop thu.