The nuclear symbol for uranium-235 should be written as O U-235.
225
92 U
233
143U
OU

²³⁵₉₂U

Explanation:

The right symbol for the nuclei is ²³⁵₉₂U;

 For this chemical element, the atom is represented by the symbol U;

 To the superscript before the symbol is the mass number

 The subscript before the symbol is the atomic number

Mass number is the number of protons and neutrons

Atomic number is the number of protons.

The two theories were:

1.Geocentric theory stating that earth is the centre of the universe and sun revolves around it.

2.Heliocentric theory stating that the earth revolves around the sun.