Math and science skills Please answer

1.
|Predict|
2.
|Use variables|
3.
|Plan and conduct investigations|
4.
Draw conclusions
5.
Hypothesize
6.
Measure
7.
Classify and order
8.
Record and display data
9.
|Use time and space relationships|
10.
Use numbers

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:

the answer is d.) potassium