Which statement about reaction rates is true? changing the amount of reactants will not change the reaction rate. changing the temperature cannot speed up a reaction rate. changing the surface area affects the reaction rate. a catalyst slows down the reaction rate.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Kelly ran electricity though a sample of water using electrolysis. the water changed into two gases, x and y. it was not possible to break down the gases x and y into simpler particles.

This map shows how climate change might affect precipitation patterns in the great plains of the united states by the end of this century. brown shoes a decrease in percipitation, and blue shows an increase. the maps differ based on the predictive levels of green house emissions. the maps shows that northern area should get a. more pracipations regardless of emmissions b. less pracipation, regardless of emmissions levels c. more precipitation, but only when emission levels.southern areas show a. more pracipations regardless of emmissions b. less pracipation, regardless of emmissions levels c. more precipitation, but only when emission levels.to use these maps to prepare for natural disasters in the great plains, scientist need to ask? a. how many tons of emissions were used at the basis of the map.b. which types of fossil fuels are used in the great plains c. if you think the above is wrong it's probly c the question is cut off