Stella thinks that if people are exposed ultraviolet light then they are more likely get skin cancer. stella designs an experiment wherein sample a consisted of people were exposed to ultraviolet light and sample b was not.
what is the control group?

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d. a round-trip ride to school and back

During convection, less dense fluid rises and denser fluid sinks.