Question

Which of the following represents the correct combination without any exception?

	Characteristics	Class
1	Sucking and circular mouth, jaws absent, integument without scales, paired appendages	Cyclostomata
2	Body covered with feathers, skin moist and glandular, forelimbs form wings, lungs with air sacs	Aves
3	Mammary gland, the hair on the body, pinnae, two pairs of limbs	Mammalia
4	Mouth ventral, gills without operculum, skin with placoid scales, persistent notochord	Chondrichthyes

• A. 3
• B. 1
• C. 2
• D. 4

Answer 1

The correct option is D 4

• Cyclostomata have sucking and circular mouth without jaws. Median fins (appendages) are present but paired fins (appendages) are absent. Integuments are without scales.
• In aves, forelimbs are modified into wings for flying and hind limbs are used for walking and running. The body is covered with feathers.skin is thin, dry and non-glandular. Lungs have air sacs.
• In mammals, mammary glands are present for the nourishment of the young ones. Hairs are present on the body. They have 2 pairs of limbs. Pinnae are absent in monotreme (mammals that lay eggs).
• Chondrichthyes have a persistent notochord, placoid scales as the exoskeleton and ventrally positioned mouth. Gill slits are not covered by an operculum.

Thus, the correct answer is option D.