Question

Which of the following represents the correct combination without any exception
`{:(,"Characteristics","Class",),((a),"Mouth ventrcal, gills without operculum, skin with placoid scales, persistent notochord","Chondrichthyes",),((b),"Sucking and circular mouth, jaws absent, integument without scales, paired appendages","Cyclostomata",),((c),"Body covered with feather, skin mosit and glandular, fore-limbs form wings, lungs from wings, lungs with air sacs","Aves",),((d),"Mammary gland, hair on body, pinnae, two pair of limbs","Mammalia",):}`
A. `{:(, "Characteristics",,,"Class"), ((1), "Mouth ventral , gills without operculum , skin with placoid scales , persistent notochord"),,, "Chondrichthyes"):} `
B. `{:(, "Characteristics",,,"Class"), ((2), "Sucking and circular mouth, jaws absent, integument without scales , paired appendages",,,"Cyclostomata"):} `
C. `{:(, "Characteristics",,,"Class"), ((3),"Body covered with feathers , skin moist and glandular , forelimbs form wings , lungs with air sacs ",,, "Aves"):} `
D. `{:(, "Characteristics",,,"Class"), ((4),"Mammary gland , hair on body , pinnae, two pairs of limbs",,, "Mammalia"):} `

Answer 1

Correct Answer - A
There are two ways of looking at this question.
First - If we consider that the examiner is asking about " no exception in given characters " in relation to the given general characters for each class then two of the given options (a and d) are correct. All characters given in (a) are true for Chondrichthyes as class and all characters given in (d) are true for Mammalia as a class.
Second - If we consider that the examiner is asking about the exception in relation to an organism belonging to the particular Class then none of the given options is fully correct.
In option (b) and (c ) one character each i.e., paired appendages and skin moist and glandular are incorrect respectively for Cyclostomata and Aves.
In option (a) Chondrichytes, the organism which is an exception to the given characters is Chimera (has an Operculum). In option (d) Mammalia the Prototherians do not have Pinna.