The wall of digestive tract is made up of four layers, which are the mucosa, tunica submucosa, muscularis and serosa.是什么意思_The wall of digestive tract is made up of four layers, which are the mucosa, tunica submucosa, muscularis and serosa.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句