Do any varieties of cyanobacteria living today produce stromatolites?
A: Yes
B: No

Blank is a rock with a find dark texture that makes up the oceanic crust

Analyze how the four requirements for life were identified by scientists

Which of the following statements best distinguishes a hypothesis from a theory? a. theories are hypotheses that have been proved. b.hypotheses are guesses; theories are correct answers c. hypotheses usually are relatively narrow in scope; theories have broad explanatory power. d. theories are proved to be true; hypotheses are often contradicted by experimental results.