To reduce the rate of chemical reaction, one can reduce temperature or surface area. The addition of catalysts increases rate of reaction but decreasing the amount of reactants decreases rate of reaction. Therefore, from the choices provided, choice A is correct.
The refractive index of sea water is more than refractive index of water . so when light passes from water to sea water or from low refractive index to high refractive index , ray of light bends towards the normal . This bending is very small because the difference in refractive index is very small.