I basically need help with all questions, i don’t understand the assignment :(?

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b. slope c. benchmark d. index contour

Describe the forces both attractive and repulsive that occur as two atoms move closer together.

Which is true concerning the products and reactants of photosynthesis and cellular respiration? a. the products of photosynthesis are sugars and the reactants of cellular respiration are starches. b. the products of photosynthesis are reactants in cellular respiration. c. oxygen is needed for photosynthesis and is given off in cellular respiration.