Scientists have proven the weakening of the ozone layer.
True
False

Scientists are conducting a study on the effectiveness of a new drug on memory loss. they are giving some of the test subjects the new drug to find out if it improves their long-term memory. which are possible limitations of this study? check all that apply. a) test subjects may want to participate in additional experiments. b) test subjects may think they should be paid more. c) test subjects may get bored and want to quit early. d) test subjects may have to travel during the experiment. e) test subjects may have full-time jobs. this is multiple choice. you for the !

Which is an innovation of gymnosperms? gymnosperms are the first seed plants. gymnosperms are the first flowering plants. gymnosperms are the first vascular plants. gymnosperms are the first spore plants.

Does all the energy stored by the phytoplankton reach the top level of the pyramid