Gas exchange in an echinoderm takes place through
a. book lungs.
b. skin gills.
c. lungs.
d. none of the above.

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

Which member of the following food chain will be least affected by ddt, a pesticide water pollutant, if bio-magnification is occurring? algae> zooplankton> crayfish> leopard frog> large mouth bass

Anurse is caring for a client who is learning how to take care of a newly created colostomy. when observing a return demonstration of the colostomy irrigation, the nurse evaluates that more teaching is required when the client carries out what procedure?