Removing thermal energy from liquid water will cause it to? a. freeze b. vaporize c. condense d. sublimate

What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent  

18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.