Aiman Mustafa Mahmoud Gusti2022-05-182022-05-185535https://drepo.sdl.edu.sa/handle/20.500.14154/2229The final set of mesomorphic function is introduced and a theorem of Polya is proved in detail to determine such sets for any mesomorphic function. A close study of the zeros of some classical polynomials is given in order to determine the zeros of the successive derivatives of some mesomorphic and entire functions. Also a quick analysis of the zeros of the successive derivatives of an entire function using some restrictions on the function and its zeros is done, followed by a brief look on the most recent developments on the zero sets of entire functions.enThesis