Differentiate between the following:
$(a)$ Tube system of feather star and canal system of $Euplectella$
$(b)$ Skeleton of shark and sea horse
$(c)$ Respiratory organs of tadpole and frog
$(d)$ Forelimbs of birds and lizard
$(e)$ Skin of tree frog and human

(N/A) Feather star $(Antedon)$ possesses a water vascular system (tube system) used for locomotion and food capture. $Euplectella$ (Venus flower basket) possesses a canal system (syconoid type) that facilitates water circulation for nutrition and respiration.
$(b)$ The skeleton of a shark is cartilaginous,meaning it is composed entirely of cartilage. The skeleton of a sea horse is bony,composed of calcified plates.
$(c)$ Tadpoles are aquatic larvae that respire primarily through gills. Adult frogs are semi-terrestrial and respire through lungs,skin (cutaneous respiration),and the buccal cavity.
$(d)$ The forelimbs of birds are modified into wings for flight. The forelimbs of lizards are pentadactyl limbs adapted for crawling or walking on land.
$(e)$ The skin of a tree frog is moist,slimy,and contains mucus glands to facilitate cutaneous respiration. Human skin is dry,keratinized,and contains sweat glands for thermoregulation and excretion,along with hair follicles.