80 centimeter of atmospheric air was trapped and passed overheated Copper pieces which on reaction produced an oxide. The resultant air after reaction was found to contain 60cm of air.(i) what is the role of Copper? ​

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

What causes temperature extremes in the desert

The cretaceous period spanned the time interval between and 65 million years ago. 250 million 144 million 75 million 200 million