GRE Reading Comprehension
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Source: XDF
The two claws of the mature American lobster are decidedly different from each other. The crusher claw is short and stout; the cutter claw is long and slender. This bilateral asymmetry begins to appear in the juvenile sixth stage of development. One possible explanation is that differential use of the claws determines their asymmetry; the claw that is used more becomes the crusher.
To test this hypothesis, researchers raised lobsters in the juvenile fourth and fifth stages of development in a laboratory environment in which the lobsters could manipulate oyster chips. Under these conditions, the lobsters developed asymmetric claws, half with crusher claws on the left, and half with crusher claws on the right. In contrast, when juvenile lobsters were reared in a smooth tank without the oyster chips, the majority developed two cutter claws. This unusual configuration of symmetrical cutter claws did not change when the lobsters were subsequently placed in a manipulatable environment or when they lost and regenerated one or both claws.
Which of the following conditions does the passage suggest is a possible cause for the failure of a lobster to develop a crusher claw?
- A The loss of a claw during the third or earlier stage of development
- B The loss of a claw during the fourth or fifth stage of development
- C The loss of a claw during the sixth stage of development
- D Development in an environment devoid of material that can be manipulated
- E Development in an environment that changes frequently throughout the stages of development