In h-atom if x is radius of first bohrs orbit de broglie wavelength of an atom in 3rd orbit is a.3πx b.6πx c.9x/2 d. x/2 please I need complete explanation fast ​

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

Which element is the least metallic between cadmium, silver, zinc, or iron?

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out