In this food chain: worms--> bluebirds--> hawks, what would happen to hawks if bluebirds became extinct?

a. the hawk population would increase

b. the hawk population would decrease

c. the hawk population would stay the same

d. cannot be determined.

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

When does dna replication(make a copy of itself)?

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