Question

Which one of the following sets includes all homologous organs?
A. Hind legs of pig, duck and kangaroo
B. Wings of bats, butterfly and bird
C. Sting of honeybee, scorpion, snake
D. Tail of rat, peacock and cockroach

Answer 1

Homologous organs are the organs which are similar in structure but have different function. It helps in determining the ancestral relationship between the organisms. For example wings of birds and hind legs of horses.

Complete Answer:
To solve this question we must know about the homologous organs in the different sets as given in the question.
A. Hind legs of pig, duck and kangaroo - The bone structure and arrangement are similar in all the three but the functions are different. Duck uses its hind leg for walking, the kangaroo for jumping and pig uses its four legs for walking. All the three are the descendants of animals walking on four legs.
B. Wings of bats, butterfly and bird - The wings of bat, butterfly and birds are used for flight but differ in the structure. It is an example of analogous organs.
C. Sting of honeybee, scorpion, and snake - Snake uses poison which is delivered through fangs. It doesn’t have sting.
D. Tail of rat, peacock and cockroach - Cockroaches do not have a tail. The body is differentiated into the head thorax and abdomen.

Thus the correct answer is (A).

Note: A duck is a tetrapod which walks on four limbs. Due to adaptation and evolution, the duck started using its hind legs for walking and forelegs became arms.