What is a decay chain
a. one element decaying into another, which decays into another
b. a list of radioactive substances organized by atomic weights
c. an accumulation of particles emitted through radioactive decay
d. a list of radioactive substances organized by half life times
please help tysm

passing a magnet thought the

mixture , because iron gets attracted to magnet .

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: