Which term comes next in the series $YEB, WFD, UHG, SKI?$?

Find the missing letters for the given series from the given alternatives:
$....aaba.....bba.....bba.....abaa....b$

Find the missing letters for the given series from the given alternatives:
$.....abb......\,,....bb....a.....bbab.....ba$

Study of the following arrangement carefully and answer the questions given below.

$Q,E ,* ,P,M ,8 ,R,A ,@ ,C ,9 ,U,H,W, \# ,J,Z, ,S, \beta, Y,N ,5 ,\$ ,G,I,T$

If the first element in the above arrangement exchanges its position with the element in the $26 th$ position and the second with the one in the $25 th$ position and so on, which of the following will be in the tenth position from the left after rearrangement?

Find the missing letters for the given series from the given alternatives:
$b....ac....cc....cb...ab....ac$

Choose the correct alternative for the missing terms in the series: $Y, W, U, S, Q, ?, ?$