1) If an animal completely lacks a body cavity, it would be considered a(n)…. A)

Question

1) If an animal completely lacks a body cavity, it would be considered a(n)….

A) mesoderm

B) acoelomate

C) pseudocoelomate

D) coelomate

2) When the body of an organism is organized around a central axis, it is called

A) bilateral symmetry

B) asymmetry

C) central symmetry

D) radial symmetry

3) Echinoderms (such as star fish and sea urchins) are unique in terms of evolution because

A) they lack basic features such as tissues.

B) they were the first protostomes to evolve.

C) they are bilaterally symmetrical as larvae, but become radially symmetrical as adults.

D) All of the above

4) Which of the following is a characteristic of ALL mammals?

A) notochord

B) deuterostome

C) coelomate

5) Which of the following is NOT a principal feature seen in chordates (such as humans)?

A) pharyngeal pouches

B) postanal tail

C) protostome development

D) notochord

6) What species of human first came about about 1.5 million years ago, and successfully spread throughout Africa, Europe, and Asia before their extinction less than half a million years ago? They are also known for their arched feet and bipedal walking (meaning that they only walked up-right, and for very long distances).

A) Homo habilis

B) Homo sapiens

D) Homo neanderthalensis

C) Homo erectus

Explanation / Answer

1) Ans-B) acoelomate
An acoelomate is an animal that does not possess a body cavity.
2) Ans-D) radial symmetry
Radial symmetry is symmetry around a central axis. Eg- in a starfish.
3) Ans-C) they are bilaterally symmetrical as larvae but become radially symmetrical as adults.
Echinoderms are bilaterally symmetrical in their larval stage and develop the radially symmetrical characteristic in adults. They have cell layers, tissues and organ and coelomate and deuterostomes.

Note- I have a doubt on the answers of qs no 4, that’s why I don’t give the answer.

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