1. According to the passage the mechanism that builds limbs as different as bird wings, penguin flippers, and human hands etc. is
A. controlled through the ZPA, uses the same DNA and the same genes in different ways and only differs in the concentration of special molecules.Correct It is a rewording of the relevant information from the passage
B. controlled through the ZPA and uses the same DNA and complementary genes suited to the shape and size of the limb.INCORRECT There is no mention of any complementary genes in the passage
C. defined by the DNA coming from fish and the corresponding complement of genes activated as per the needs of the shape, size and strength of the limb.INCORRECT The passages doesn't mention anything about "DNA coming from the fish" and "genes activation"
D. controlled through the ZPA in most tetrapods with some exceptions and uses DNA from corresponding ancestral heritage of tetrapods with suitable genes turned on.INCORRECT The passage doesn't mention any exceptions.
E. not controlled through ZPA but differs from one vertebrate to another.INCORRECT This option is the opposite of the findings of the experiment. The mechanism is indeed controlled by the ZPA.
2. In the context of the passage, why was the discovery of the Tiktaalik important?
A. It proved beyond doubt and without the need of experimentation the commonality of skeletal architectures of all land based organisms.INCORRECT The discovery of Tiktaalik didn't prove the commonality. It provided the reason for the commonality.
B. It proved the reason why the architecture of limbs in various organisms was optimized for the organism’s corresponding functional needs.INCORRECT This choice state opposite information. The passage states that the architecture is not optimized. It is same as land based animals.
C. It provided the reason for commonality of skeletal architecture described earlier in the passage.CORRECT The discovery of Tiktaalik provided the reason for the commonality of skeletal architecture
D. It traced our ancestral heritage to the fish, providing the reason why we share majority of our DNA with aquatic animals.INCORRECT Sharing of DNA with aquatic animals is not mentioned.
E. It showed how ancient genes could be used in new ways for structures as diverse as wings in birds and fins in sharks.INCORRECT Mechanism of how ancient genes were used in new ways is not discussed in the passage.
3. From the passage, what can be inferred about the architecture of limbs?
A. All land-based creatures that have limbs with similar architecture are also structurally similar.INCORRECT The passage doesn't say that structure of limbs is similar
B. It is different in land-based animals due to the difference in expression of the genes.INCORRECT This option states the opposite. The architecture of all land-based creatures is similar.
C. It evolved since the time of Tiktaalik to suit the functional needs of the land-based animals.INCORRECT As per passage, the architecture of limbs didn't evolve. The last line of the passage clearly states "maintaining the similarity in architecture". Hence the architecture didn't evolve.
D. It may have been possible to develop an architecture better optimized for the functional needs of various organisms had nature not adhered to the common architectural scheme.Correct This option can be inferred from following lines.
"The reason for this inherent commonality in architecture still remained a conundrum for decades. Why did nature not develop architectures better optimized to the functional needs of various organisms?"
E. It is defined by the concentration of special molecules present in the cells of ZPA.INCORRECT Architecture is not defined by the concentration of special molecules but the structure of limbs.
4. The primary purpose of the passage is
A. To explain the reasons for the similarity in the architecture of the limbs of all land-based organisms.Correct This is the pupose of the passage.
B. To evaluate the implications of the experiments of Edgar Zwilling and John Saunders.INCORRECT Partial scope. These experiments are discussed only in paragraph 2.
C. To trace the importance of the discovery of Tiktaalik.INCORRECT Partial scope. The importance of the discovery of Tiktaalik is discussed only in paragraph 3.
D. To describe the role a common DNA plays in the unified architecture of the limbs of all land-based organisms.INCORRECT Partial scope. This is discussed only in paragraph 3.
E. To deduce how limbs of various sizes and shapes are built by the ZPA tissue.INCORRECT Partial scope. This is discussed only in paragraph 2.
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