Hello I need help , if anyone could help me u would really appreciate it you have to flip it :)

*will mark brainliest to first correct answer* photosynthesis led to increasing levels during the later proterozoic eon? a. oxygen b. water c. carbon dioxide d. none of the above

Write a paragraph at least 5 sentences “why all vaccinations should be mandatory”

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 !