Which of the following occurs when a substance changes its state of matter (e.g., from a liquid to a gas or from a solid to a liquid)?
A. Both the amount of heat and the temperature change.
B. Neither the amount of heat nor the temperature changes.
C.
The amount of heat does not change, but the temperature changes,
D.
The amount of heat changes, but the temperature does not change.

C.  

The amount of heat changes, but the temperature does not change.

Explanation:

When a substance changes its state or phase of matter, the amount of heat changes, but the temperature does not change. For example, if water changes from solid ice to liquid water, it absorbs more heat energy, but its temperature remains at the freezing point/melting point of 0°C (32°F).

As the right side of a frog's heart receives deoxygenated blood from the body, and the left side receives freshly oxygenated blood from the lungs, the two streams of blood mix together in the ventricle, sending out a concoction that is not fully oxygenated to the rest of the frog's body.