They - along with your choice ot major and minor skills and birthsing - are just starting attributes. The nearest place you could learn about starting attributes and racial bonuses
is here.
The question about faster leveling in Morrowind is almost meanigless, level is much less important here as it is in other games.
Getting a level in Morrowind means just follwing:
- 10% or your former Endurace is added to your Health;
- you can increase 3 Attributes (Strength ... Luck);
- the random spawn of creatures and the loot is adjusted a bit to your level;
Attributes and skills are what really matters, not level.
Choosing right combo of race, profession and birthsign you can improve the starting conditions (and lower max.level you could get at the end).
For example, you took some combat profession with Long Sword as one of major skils. Since it is major, you get basical 30 points in it by start (15 if it was a minor skill). Then you've choosed Redguard with his 15 bonus, now it becomes 45 (in reverse order in fact). Howver, a Breton, though started with 30 skill, could make 1.5 level more on Long Sword futher in game, altogether he won't be so good with it at the begining.
It's said that major skills grow faster than other, misc ones slower. Not that very noticable, IMHO.
The max. number to increase any attribute you could achieve on level-up is 5 - supposing that you had grown corresponging skills by 10 in total (say, 4 in Spear, 4 in Heavy Armor and 2 in Medium Armor would give you the chance to increase Endurance by 5). The minimun is obviously 1. 3 Attributes (no more and no less) can be increased on every level up.
No skill could pass 100 in natural way (though you could temporary boost them over if you had obtained Fortify Skill spell one or another way). So, naturally, as soon your major and minor skills are all 100 you could gain no new levels.
P.S. Misc skills do not help in leveling up, altogether they still help to raise stats. In most early version on PC (and perhaps also on xbox plain Morrowind) you shouldn't use trainers to raise a misc skill to gain in stats, though. In latter versions it had been changed and there wasn't any difference between taking classes and exercising any more.
Oh, and a thing somebody miss : you get skill increase just successfully using the skill. You get no revards in any kind of points for killing something (other that for using a skill), though there may be quests the quest giver would "teach" you (usually 1 level more) in certai skill as a reward.