In the formula H2SO4, what is the 4 called?

Which statement describes how phase changes can be diagrammed as a substance is heated? the phase is on the y-axis and the temperature is on the x-axis. the temperature is on the y-axis and the phase is on the x-axis. the time is on the y-axis and the temperature is on the x-axis. the temperature is on the y-axis and the time is on the x-axis.

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

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