What effect does a catalyst have on a reaction? O A. A catalyst increases the concentrations of products.
O B. A catalyst makes it possible for a reaction to happen.
O C. A catalyst speeds up the rate of a reaction.
O D. A catalyst contributes energy to a reaction.

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.

give me abc and i will get it for u.

i believe the answer is three water molecules