Is boiling salt water until just salt remains a physical or chemical change?

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

What is the name of the enzyme that forms at the start of transcription?

Which statement best describes the liquid state of matter? a. it has definite shape but indefinite volume. b. it has definite shape and definite volume. c. it has indefinite shape and indefinite volume. d. it has indefinite shape but definite volume.