What action will slow down the rate of a reaction?
a. raising the temperature of the reactants
b. decreasing surface area of a solid reactant
c. increasing the concentration of the reactants
d. adding a catalyst to the reaction

B. Decreasing the surface area of solid reactant;
Why? Collision theory suggests that the more opportunities for reactants to come into contact or "collide" with other reactants, the faster the reaction will take place. Hence, decreasing the surface area will decrease the probability of collisions between reactants thereby decreasing reaction rate.

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.