Chondrichthyes have the following except A. True Bone B Teeth C. Scales D. Jaws

Question

Chondrichthyes have the following except A. True Bone B Teeth C. Scales D. Jaws Alt tetrapods/Four-legged animals are descended from A. lobe-finned fishes B. Bony fishes C. Cartilaginous fishes D. Ray-finned fishes Echinoderms have __ symmetry as larva and __ symmetry as adults A. radial as larva, radial as adults B. bilateral as larva, radial as adults C. no symmetry as larva, radial as adults D. bilateral as larva, bilateral as adults What is an advantage of a hardened exoskeleton ? A. A stronger source of protection B. A secure site for muscle attachment C. An improvement in locomotion and flight D. AM the above What are the structures that are used for respiration m most arthropods A. Spiracles B Thacheoles C. Air Sacs D. Tracheae E. All of these Joints allow for flexibility between hard segments __ via and __ sections A. Thin, flexible B. Thick flexible C. Thin, inflexible D. Thick, inflexible The bodies of animals belonging to the class Arachnids are generally deeded into how many Tagmata's A. 2 B. 1 C. 4 D. 8 Why are insects so successful? A Small size B. Adaptable exoskeleton C. High birthrate/ short generation time D. All the above What part of an insect's body do all legs arise from? A. head B. Thorax C. Abdomen D. Wings

Explanation / Answer

Q 10. B. Bony fishes,

Bony fish or Osteichthyes have their skeleton made up of bone tissues. This group of fishes are divided into ray-finned fishes and lobe-finned fishes. Hence the answer is bony fishes.

Q.11. B. Bilateral as larva, radial as adults

Echinoderms include marine animals such as sea stars, sea urchins, sand dollars, sea cucumbers etc. At the larval stage, all of them have bilateral symmetry, that is lost while metamorphosis and in the adult stage they develops radial symmetry.

Q12.D all the above

The hardened exoskeleton supports animal’s tissues, exoskeletons prevent them from drying out. They also act as the joining point for all the muscles of that particular animal. Hence the answer is all of the above.

Q13.E. all of the above

In arthropods, the tracheal system helps to carry oxygen into the body cells. the tracheae are branched into finer branches and these branches are called Tracheoles. Spiracles regulate the flow of air and prevent the loss of moisture from the body. In some of the species, air sacs are present for oxygen supply.

Q14. B. Thick, flexible

Q15.A. 2

The body of  arachnids have divided two tagmata: (1) the cephalothorax and the (2) abdomen

Q16.D all of the above

The exoskeleton helps them to protect the soft tissues of the body. Because of their small size, they can survive with lesser resources. The short generation time also helps them to grow their number faster that again helps in the survival of the species.

Q17.B. Thorax

In an insect's body, all the legs arise from the thorax. It is the anchor point for legs and wings.

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