Answer:
List the features of gas exchange surfaces in animals.
1)They are moist to prevent the cells from drying and to allow gases to dissolve;
2)They have a large surface area , so that a lot of gas can diffuse across at the same time;
3)They have a high concentration gradient - maintained by the movement of air & blood.
True they are in the heart as well as the rest of your body
Sources of heat from inside earth is radioactive decay and residual heat.
