What tells the number of protons in the nucleus of every atom of an element

The most efficient way to establish the best possible economizer position is to measure

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

In which of these cases are the two wave points considered to be in phase with each other?