Which comes first: embryonic development or fetal development?

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

Astudent observes a star from two positions of earth in its orbit, in summer and winter, and measures the change in the position of the star. which of these can be best calculated by this method?

What is the name of the two satelites on mars