Explain the 3 plate boundaries? Plz I really need help

Coquina, a type of limestone, forms from shell fragments that settle on the ocean floor. what type of rock is coquina?

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

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.