What are the sources of error in determination of boiling point and melting point?

Idon’t know how to solve this question

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.

What two factors can affect the properties of a hydrocarbon? a. the number of its carbon atoms and the number of single bonds b. the number of its carbon atoms and the arrangement of its atoms c. the arrangement of its atoms and the number of its double bonds