Problems with elemental resistances.

I am playing ranger on merciless.For me is not clear the mechanic of resistances,because I´ve had about 95% for all resistances at level 50 and now on level 60 left only 1% fire,16% cold and 45% lightning and 60% chaos.I have about 5400 evasion and maybe this is the reason why I lost them.Would you like somebody explain these relations between level ups and resistances.How does it work please?

Level and resistances have no relation, the game just has resist penalties like in many other games of the genre. In normal there is no penalty, in cruel you get -20% and in merciless -60%.

What will usually change with level is your chance to hit, armor reduction and chance to evade estimates, because they get compared against monsters of higher level and your stats probably haven't changed much (you do get a small amount of accuracy and evasion on each level but those values are awfully small).