All cells are not the same because..

The simple answer is that all cells are not same due to the vast difference in their internal structures.
For example two type of cells are:
1) Prokaryotic: these cells have no nucleous and they are small and simple.
2) Eukaryotic: These cells have a neucleous and are large and complex as opposed to prokaryotic.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.