Sn=1 O=2 H=4 Sn=1 O=1 H=2
Balanced or unbalanced?

relative humidity is a measure of the amount of moisture in the air relative to the total amount of moisture the air can hold.

so d

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

a polar bond is formed when electrons are shared unevenly between atoms