What are the examples of liquid changing into solid matter?
Since there are quite a few types of solid matter that can be melted, there are numerous examples. The most common example would probably be water being frozen into ice cubes.
Yes it does. Changing between the forms requires energy to be lost or gained depending on the direction the substance is changing. Changing from solid to liquid or gas and changing from liquid to gas both require inputs of energy to the substance, and changing from gas to liquid or solid or from liquid to solid releases energy from the substance to the environment, all at constant temperature.
Which sentence tells about changing matter without changing its state is it freeze water or melt ice?
State of matter is referring to a substances existence as a solid, liquid, or gas. So, a common example would be solid water (we call it ice) changing state to liquid water due to the addition of energy (possibly heat). If energy continues to enter the system the liquid water will change state again to become a gas (steam).