Question

Main excretory organ in a frog are
A. Skin
B. Lungs
C. Kidney
D. Malpighian tubules

Answer 1

Hint: Frogs can live both on land and in freshwater and belong to class amphibia of phylum chordata . The most common species of frog found in India is Rana tigrina .

Complete answer:The elimination of nitrogenous waste is carried out by a well developed excretory system in frogs . The excretory system consists of a pair of kidneys , ureters cloaca and urinary bladder . These are compact dark , red and bean like structures situated a little posteriorly in the body cavity on both sides of the vertebral column .
Each kidney is composed of several structural and functional units called uriniferous tubules of nephrons . Two ureters emerge from the kidney in the male frog . The ureters act as a urinogenital duct which opens into the cloaca . In females the ureters and oviduct open separately in the cloaca . The thin walled urinary bladder is present ventral to the rectum which also opens in the cloaca . The frog excretes urea and thus is a ureotelic animal . Excretory waste is carried by blood into the kidney where it is separated and excreted . So the main excretory organ of frogs is the kidney .
So, the correct answer is ( C )

Additional Information: Frogs do not have constant body temperature that means their body temperature varies with the temperature of the environment . Such animals are called cold blooded or poikilotherms .
You might also notice changes in the colour of the frog while there in grasses and or dry land . They have the ability to change the colour to hide them from their enemies which is known as camouflage . This protective coloration is called mimicry .

Note: Frogs are not seen during peak summer and winter during this period they take shelter in deep burrows to protect them from extreme heat and cold this is called a summer sleep or aestivation and winter sleep or hibernation respectively .