What statement about gases is true?

The reaction q+r2=r2q is found to be first order in r2 and

The diagram shows the structures of horse and cat forelimbs. what does the diagram suggest about the evolutionary relationship between these two mammals? a. they have homologous structures, indicating a common ancestor. b. they have analogous structures, indicating a common ancestor. c. they have homologous structures, indicating that they do not have a common ancestor. d. they have analogous structures, indicating that they do not have a common ancestor.

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.