Answer:
Test a known bloodstain as a positive control and a blank (filter paper) as a negative control (see interpretation of results to determine a positive and negative result).
Volcanoes influence our lives by shaping the land around us as they form, making the soil fertile and creating havoc when they erupt.
The natural succession of a small farm pond will tend to make the pond more likely to freeze solid in winter time,the nature of things helps them to merge more quickly and adapt to their environment.