Please help!! BE QUICK PLEASE! THIS IS A TEST (BTW this is science)

Which property of a rock remains unchanged by mechanical weathering? a. total surface area b. size and shape c. mineral composition d. sharpness

The activation energy for the reaction no2(g)+co2(g)⟶no(g)+co(g) is ea = 300 kj/mol and the change in enthalpy for the reaction is δh = -100 kj/mol . what is the activation energy for the reverse reaction?

Which process results in the release of energy stored in the products of photosynthesis? a. polymer synthesis b. depolymerization c. digestion d. cellular respiration