Epithelial tissue.
Other three types of tissues present in animals are : Muscular tissues, connective tissues and nervous tissues.
Functions
(i) Epithelial tissue covers the body surface as an outer layer of skin and provides protection to the underlying tissues from mechanical injury, entry of germs and harmful chemicals.
(ii) If forms the inner lining of mouth, alimentary canal and other internal organs inside the body and protect these organs.
(iii) Epithelial lining of intestive absorbs water and digrested food.