Both coal and diamonds are forms of elemental carbon. coal is brittle while diamonds are considered to be the hardest of all substances known. what is the appropriate justification for this?

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.