Answer has to be in two significant figures

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.

The chemical bond connecting one nucleotide with the next one along the nucleic acid chain is called a

What is the most important factor in determining climates.