What elements are humans mostly made of

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

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?