C)All vertebrates are chordates D) Echinoderms and chordayes are deuterostomes E

Question

C)All vertebrates are chordates D) Echinoderms and chordayes are deuterostomes E) Sea squirts and lancelets are invertebrates The correct sequence in insect complete metamorphosis is: A) eggimmature formadult B) egg--> trochophore larva..? veliger larva-…? adult C) egg. puplarva. adult D) egg-? larva.…? pupa-? adult El adult larvaegg >pupa. 44. Which of the following is a shared derived character of mammals? A) placenta B) 45. amnion three middle -ear bones O) endostyle E) notochord. C) A shark is characterized by A) placoid scales B) bony skeleton C) water vascular system D) amnion E) muscular diaphragm 46. Which of the following is NOT characteristic of birds? A) hollow bones B) ectothermy C) amnion D) high metabolic rate E) reptilian-like scales on legs 47. Which of the following is characteristic of insects? A) biramous appendages B) mandibles C) chelicerae D) eight legs E) two pairs of antennae 48. Protostomes are characterized by A) spiral cleavage B) indeterminate cleavage 49. C) enterocoely D) radial symmetry E) a distinctive body plan that includes a pseudocoelom.

Explanation / Answer

Ans 44: D

Cycle starts from a simple cell, the egg. This egg metamorphoses to the larva metamorphoses to pupa, which is referred to as the stage of complete metamorphosis and from which the mature adult emerges post breakdown and replacement of tissues and organs of the larvae into adult tissues and organs. The adult stage is the stage from maturity onwards.

Ans 45. C

Trihelodontids, which means three middle ear bones, is a shared derived characteristic of mammals.

Ans 46. A

Placoid scales though scales are more of a modified teeth that cover the body of the shark. Placoid scales are covered with enamel.

Ans 47. B

Birds need to generate heat form within their body to maintain their body temperature. So they are endothermic and not ectothermic like reptiles which need to seek out external sources to regulate their body temperatures.

Ans 48. C

Insects do not have chelicerae. They have mandibles.

Ans 49. A

During the gastrulation stage of early embryo, protostomes develop the mouth while the deuterostomes develop the anuus. The difference between protostomes and deuterostomes lies in the fact that the mouth in protostomes develops before the anuus does and in deuterostomes, the anuus develops before the mouth does.

Also, in protostomes, we see spiral and determinate cleavage, whereas in deuterostomes, we see radial and indeterminate cleavage.

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