heat and pressure
When matter changes state, the amount of mass and the amount of energy are always conserved. This means that the total mass and energy of the system remain constant throughout the phase change.
breaking or creating molecular bonds -- increasing or decreasing heat energy
Light
All matter has mass and volume.
"The" two changes are wrong. There are lots of different states of matter, and therefore many different possible transitions. The most commonly studied states of matter are solid, liquid, and gas; each of them can change directly to each of the others, for a total of 6 types of change.
I would suggest temperature and pressure.
Two types of changes in matter are physical changes and chemical changes. Physical changes involve a change in appearance, such as a change in shape or state, without forming new substances. Chemical changes involve a rearrangement of atoms to form new substances with different chemical properties.
A low birth rate and environmental hazards are two things that can cause a population to decrease.
A low Birth Rate and environmental hazards are two things that can cause a population to decrease.
nothing
The question is too ambiguous to answer. You may as well ask "what two things can cause error in geography"?
All things should fall into the following two categories: Matter and not-matter. Anything physical (eg. a rock) is made of matter, anything spiritual, relationship orientated or arsey science suggestion is not-matter.