What is vestigial structure​

Vestigiality is the retention during the process of evolution of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species

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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. Noun. (plural vestigial structures) (biology) A structure in an organism that has lost all or most of its original function in the course of evolution, such as human appendixes. structure in an organism that has lost all or most of its original function in the course of evolution, such as human appendixes.

Explanation:

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.