CONCEPTS: atom, element, formula, molecule, number

GEN: molecular formulas the count of the actual number of atoms of each element in a molecule .

CONCEPTS: bottom, run, staircase

GEN: Someone runs down a staircase as people scramble from the bottom of a different staircase.

CONCEPTS: forest, hill, road

GEN: road going through hills into the forest

CONCEPTS: home, improve, value

GEN:
improve the curb appeal and value of your home with new windows