They are still teaching in schools embryo's have gill slits? This was proven fraud. No wonder your confused, your being taught lies.
It began with Evolutionist and German zoologist Ernst Haeckel in his 1876 book General Morphology of Organisms. Haeckel fraudulently presented altered, misleading and misinterpreted evidence. Some of the key details of his embryo drawings were wrong - purposely altered to make a case for Evolution where none existed. As for those "gill slits" - In the human embryo at one month, there are wrinkles (flexion folds) in the skin where the throat pouches grow out.
You were lied too.
The appendix is not useless or God/Evolution would not have created it. Look on wiki for the uses of the appendix, there is plenty. Yes we can live without it, but you can also live without your hair, finger nails, left hand, take your pick. Are those on the list to go next?
It seems your being confused with people feeding you false information. I hope you do some independent research and prove these suckas wrong.