*Question*
Q: What do you call structures like a whale's pelvic bones, which were once attached to legs, or wings that cannot be used for flight? Choices: - primitive - primordial - distinctive - vestigial A:
**Answer**
vestigial

*Question*
Q: What subphylum, which includes crabs and crayfish, represents the dominant aquatic arthropods? Choices: - arachnids - sponges - invertebrates - crustaceans A:
**Answer**
crustaceans

*Question*
Q: The concentration of a substance is the quantity of solute present in a given quantity of ___________? Choices: - structure - mixture - salutation - solution A:
**Answer**
solution

*Question*
Q: Depending on the surrounding conditions, normal matter usually exists as one of three phases: solid, liquid, or this? Choices: - fluid - crystal - ice - gas A:
**Answer**
gas