Question

Match the following classes of chordates with suitable characteristics.

• A. Two-chambered heart
• B. Pneumatic bones
• C. Rough horny scales
• D. Hairs on their skin

Answer 1

$\bullet$Pisces, have an S- shaped two chambered heart, with one atrium and one ventricle. Blood circulation is of single type. These are cold-blooded organisms, which means their body temperature depends on the surrounding temperature.
$\bullet$Reptiles, the first class of vertebrates, adapted completely for terrestrial life. Their skin is dry, cornified and is devoid of glands. It is protected by an exoskeleton of horny scales, which is an important adaptation for terrestrial mode of life.
$\bullet$The endoskeleton of birds is bony. Bones, here are pneumatic i.e., contain air cavities, which helps them to reduce weight and helps them in flying.
$\bullet$The skin of the mammals is unique in possessing hairs. The body of mammals is covered by elastic glandular skin, which is protected by epidermal hair.