How do animals contribute to the carbon cycle

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 did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen

How does the diagram explain ocean currents? earth tilt 23.5 degreesquestion 1 options: earth's tilt causes uneven heating of earth which causes currents.earth's tilt causes the ocean to move because of gravity.earth's tilt and its rotation cause currents.earth's tilt causes uneven distribution of salt which causes currents.