question_answer 33)

  Which among the following have scales? (i) Amphibians                  (ii) Pisces                              (iii) Reptiles                        (iv) Mammals (a) (i) and (iii)                     (b) (iii) and (iv)                  (c) (ii) and (iii)                    (d) (i) and (ii)

Answer:

  (c) Fish, along with reptiles, have hard protective scales on their skin for protection. The outer body of many fish is covered with scales, which are part of the fish's integumentary system. The scales originate from the mesoderm (skin). One major characteristic of reptiles is the presence of scales composed of a protein called keratin. These scales form a waterproof barrier of skin, which allows reptiles to exist away from water without the threat of dehydration. Amphibians use their skin as secondary respiratory surfaces. Their skin is permeable to water and gases and is 'lined by mucous.