Question

while observing permanent slide of of amoeba, i saw oval shaped nucleus. this nucleus indicates

Answer 1

following are the two observations that concludes that the slide shows binary fission in Amoeba:

Nucleus division is followed by the division of cytoplasm

A single cell splitting into two identical cells

Answer 2

Here in this case you have witnessed the initial stage of amoeba's reproduction.  

Amoeba reproduces through the asexual reproduction method in which the single organism undergoes fission. In this method, the organism divides itself to form two equal size organism. The organism broke itself into two along with its genetic materials that results in identical twin of the organism in both genetic and virtual manner.