When the elements combine form compounds, they do it to become stable. They give and taker the outside electrons or by sharing outer ring electrons.
The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. Protons have a positive charge (+) and electrons have a negative charge (-). The positive charge of the protons is equal to the negative charge of the electrons.
.answer:
so the first one is analogous
the second is homologous
and the third is analogous
explanation:
analogous. this means they share a similar function (flight) but do not have the same embryonic origin.