EVOLUTION
EVIDENCE FOR EVOLUTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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structures that grow and improve in function as they are used
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structures that function at certain times of the year
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structures that will become adaptations when the environment changes
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structures that have lost all or most of their function over time
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Detailed explanation-1: -According to the question, the small bones in the whale is might have functioned in the ancestor period but not in the current time due to the course of the evolution. Hence, the correct answer is D that structures that have lost all or most of their function over evolutionary time.
Detailed explanation-2: -These unused structures without function are called vestigial structures. Other examples of vestigial structures are wings on flightless birds, leaves on some cacti, and hind leg bones in whales.
Detailed explanation-3: -The pelvic bones of whales are “one of the classic examples of a vestigial structure, ” said Otárola-Castillo. “But what we found was that the shapes of these bones are highly associated with the mating systems of these whales and dolphins-species that are more promiscuous have more-complex-shaped pelves.”
Detailed explanation-4: -Structures that have no apparent function and appear to be residual parts from a past ancestor are called vestigial structures. Examples of vestigial structures include the human appendix, the pelvic bone of a snake, and the wings of flightless birds.
Detailed explanation-5: -Other vestigial reports on sea mammals could be cited, but enough has been presented to show that these rudimentary hind limbs do exist in cetaceans and are truly vestigial. Being vestigial, they point to an earlier stage of evolutionary development.