MCQ
What are the characteristics of alveoli?
- ✓Very thin, irregular walled and highly vascularised
- BThick and smooth membrane
- CNetwork of blood capillaries and thick-walled
- DThick, regular walled and lack of blood vessels
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
$A$. This disorder was first described by Langdon Down $(1866)$.
$B$. Such an individual has overall masculine development. However, the feminine developement is also expressed.
$C$. The affected individual is short statured.
$D$. Physical, psychomotor and mental development is retarded.
$E$. Such individuals are sterile.
Choose the correct answer from the options given below:
| Option | Characteristics | Class |
| $(a)$ | Sucking and circular mouth; jaws absent, integument without scales; paired appendages. | Cyclostomata |
| $(b)$ | Body covered with feathers; skin moist and glandular, fore-lims form wings; lungs with air sacs. | Aves |
| $(c)$ | Mammary gland; hair on body; pinnae; two pairs of limbs. | Mammalia |
| $(d)$ | Mouth ventral; gills without operculum; skin with placoid scales; persistent notochord. | Chondrichthyes |