Select the correct answer from each drop-down menu. When Raymond observes certain natural phenomena, he often forms ideas about their causes and effects. Suppose that Raymond
surmises that leaves change color in autumn due to scarcity of sunlight. In order to test whether his idea is accurate, he must first
construct a falsifiable
that defines a clear relationship between two variables. Raymond's next step is to
that would isolate and test the relationship between the two variables. This task can be pretty
daunting because Raymond will need to identify and eliminate any
variables that could confuse test results.

Oxidation-reduction reactions (often called "redox" for short) are reactions that involve the transfer of electrons from one species to another. oxidation states, or oxidation numbers, allow chemists to keep track of these electron transfers. in general, one element will lose electrons (oxidation), with the result that it will increase in oxidation number, and another element will gain electrons (reduction), thereby decreasing in oxidation number. the species that is oxidized is called the reducing agent or reductant. the species that is reduced is called the oxidizing agent or oxidant. to sum up: oxidation = increase in oxidation state = loss of electrons = reducing agent reduction = decrease in oxidation state = gain of electrons = oxidizing agent part a which element is oxidized in this reaction? fe2o3+3co→2fe+3co2 enter the elemental symbol. view available hint(s) is oxidized part b which element is reduced in this reaction? 2hcl+2kmno4+3h2c2o4→6co2+2mno2+2kcl+4h2o enter the elemental symbol. view available hint(s) is reduced