Question

Which one of the following is not a characteristic feature of frog?

• A. The skin is moist and slimy.
• B. Each of the fore limbs and hind limbs end in five digits.
• C. Hepatic portal and renal portal systems are present.
• D. Skin, buccal cavity and lungs are the respiratory organs.
• E. Heart is three-chambered.

Answer 1

Answer: (B)

Each of the fore limbs and hind limbs end in five digits.

• Frogs have moist and slimy skin because they are covered in a mucous coating. This coating helps them keep their skin moist which helps them breathe through their skin.
• Option B is incorrect because the frog's forelimbs end in four digits and the hind limbs in five digits.
• Apart from skin frogs also respire through the bucco-pharyngeal cavity and lungs.
• The Hepatic (liver) portal system collects blood from the intestine and passes it to the liver and the renal (kidney) portal system collects blood from renal glomeruli and passes it to the peritubular plexus (the blood capillaries that surrounds the proximal and distal convoluted tubules). Both hepatic and renal portal systems are found in frogs.
  
• Heart in frogs is 3-chambered with 2 auricles and 1 ventricle.

Thus, the correct answer is option (B), 'Each of the forelimbs and hind limbs end in five digits'.