Which structures are at the terminal end of the respiratory system?

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

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above