Which equation is balanced? Mg3N2 + H2O + 3MgO + 2NH3
C3H8 + 502 + H2O + 3CO2
Zn + 2HCl → ZnCl2 + H2
3H2SO4 + 2Fe + Fe2(SO4)3 + H2

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

Can someone me with 1 to 4 plz. fast

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?