HELP PLEASE 13. In the collection of data, list at least 3 important constants (also known as "controlled variable

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? a. the wings are analogous structures that evolved differently and do not have a similar internal structure. b. the wings are homologous structures that evolved differently and do not have a similar internal structure. c. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. d. wings of bats are vestigial structures, but the wing structures of birds are not vestigial

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