Which of the following is not an example of chemical weathering?
a.
natural plant acid breaking down a rock
c.
oxidation of metals
b.
acid rain deteriorating a marble statue
d.
ice wedging in rock

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

Cells destroy body cells infected by a virus or bacteria. killer t t memory t none of the above

10. in which phase will crossing-over occur? a. mitosis b. metaphase ii c. prophase i d. meiosis ii