Nearly 97% of the water on earth is unusable by humans because of its this lack of usability is due to the fact that water 1. a. temperature. b. salinity. c. impurities. 2. a. is a universal solvent. b. expands upon freezing. c. is transparent.

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.