If a particular substance has a half-life of 8 years, what is the annual decay rate for this substance?

c is the answer because when something is left after something evaporates that shows the chemical change.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

answer; capital earns interest; entrepreneurship receives a profit or incurs a loss;