1.
Here are the Ice Troll's Offense stats, and I have some questions about them:
Speed 30 ft.
Melee battleaxe +7 (2d6+4), bite +2 (1d6+2), claw +2 (1d4+2) or
bite +7 (1d6+4), 2 claws +7 (1d4+4)
Space 10 ft.; Reach 10 ft.
Special Attacks rend (2 claws, 1d6+6)
First of all, when it says "claw +2 (1d4+2) or bite +7 (1d6+4)", is that a full round action like the 2 claws +7 (just you can only use one of the attacks), or is it just two normal attacks (and if so, why isn't there a comma in between them). Secondly, what is rend? Does rend have a +7 or +2 attack bonus, and why does rend do so much more damage than all the other attacks, wouldn't the troll never use the bite +2 if he could use the bite +7, or the regular two claws if he could use rend?
2. This is a simple question: What is a readied action?
The troll has two possible full attack sequences:
battleaxe +7 (2d6+4), bite +2 (1d6+2), claw +2 (1d4+2)
or
bite +7 (1d6+4), 2 claws +7 (1d4+4)
He could choose to perform either sequence on a full attack. If he is unable to full-attack he would get only a single attack (per a standard action) and would likely choose the battleaxe because it has the highest attack bonus and damage.
On a full attack if he choose to use both claws in the round (meaning he can't use his battleaxe) he could get bonus damage from Rend if he hits with both claws. Provided the Troll hits with both claws he automatically also deals rend damage. There is no roll to hit with it, it was accomplished when both claw attacks hit.
Rend is a special effect.
Rend (Ex) If it hits with two or more natural attacks in 1 round, a creature with the rend special attack can cause tremendous damage by latching onto the opponent's body and tearing flesh. This attack deals an additional amount of damage, but no more than once per round. The type of attacks that must hit and the additional damage are included in the creature's description. The additional damage is usually equal to the damage caused by one of the attacks plus 1-1/2 times the creature's Strength bonus. Format: rend (2 claws, 1d8+9); Location: Special Attacks.
With the bite, both claws, and rend the troll has a greater potential damage output than if he uses he first attack sequence. But, if he misses with either of the claws he also misses out on the rend damage completely and his damage output will likely be below the first attack sequence. Also, the difference in attack bonuses between the two sequences is due to the natural attacks being used in conjunciton with manufactured weapons.
Natural Attacks Most creatures possess one or more natural attacks (attacks made without a weapon). These attacks fall into one of two categories, primary and secondary attacks. Primary attacks are made using the creature's full base attack bonus and add the creature's full Strength bonus on damage rolls. Secondary attacks are made using the creature's base attack bonus –5 and add only 1/2 the creature's Strength bonus on damage rolls. If a creature has only one natural attack, it is always made using the creature's full base attack bonus and adds 1-1/2 times the creature's Strength bonus on damage rolls. This increase does not apply if the creature has multiple attacks but only takes one. If a creature has only one type of attack, but has multiple attacks per round, that attack is treated as a primary attack, regardless of its type. The natural attacks by size table lists some of the most common types of natural attacks and their classifications.
Some creatures treat one or more of their attacks differently, such as dragons, which always receive 1-1/2 times their Strength bonus on damage rolls with their bite attack. These exceptions are noted in the creature's description.
Creatures with natural attacks and attacks made with weapons can use both as part of a full attack action (although often a creature must forgo one natural attack for each weapon clutched in that limb, be it a claw, tentacle, or slam). Such creatures attack with their weapons normally but treat all of their available natural attacks as secondary attacks during that attack, regardless of the attack's original type.
Readied acitons allow you to do something in response to a specific aciton.
Readying an Action: You can ready a standard action, a move action, a swift action, or a free action. To do so, specify the action you will take and the conditions under which you will take it. Then, anytime before your next action, you may take the readied action in response to that condition. The action occurs just before the action that triggers it. If the triggered action is part of another character's activities, you interrupt the other character. Assuming he is still capable of doing so, he continues his actions once you complete your readied action. Your initiative result changes. For the rest of the encounter, your initiative result is the count on which you took the readied action, and you act immediately ahead of the character whose action triggered your readied action.
You can take a 5-foot step as part of your readied action, but only if you don't otherwise move any distance during the round.
1) A standard attack is any single weapon listed in the melee block. So the battleaxe, the bite at +7, or one claw. What the block explains is two options for full attack. If it has a battleaxe, then the full attack is Battleaxe, Bite, Claw. Alternatively, if it has no weapon, then it is only Bite, Claw, Claw. There is no comma because it is really two separate groups of words divided by 'or'. You cannot mix and match from these two sets.
Rend is extra damage you get for free if you hit with both claws. It has no to-hit bonus of its own because it is free extra damage.
As for the Bite +2 and a different Bite +7 is because of secondary natural weapon attacks. Some natural attacks are always secondary, like the claws. In other cases, when you mix manufactured weapons (the battleaxe) with natural attacks (claws, bite), the natural weapons become secondary. This means the attack bonus drops by 5 and the damage bonus is only half strength. That's why, if you take the second attack profile (bite, claw, claw) the bite is back to full strength. Also, if you choose just to bite as a standard melee attack, the bite is at full strength because it isn't being mixed in with the battleaxe.
2) This is a bit complex.
On your turn, you can take a standard action to 'ready' a different standard action for a specific trigger event. For example, I have a crossbow and move over to stand 20 feet away from a closed door. I then say "I ready an action to shoot the first thing I see through the door." Now, that could be the goblin who opens the door, it could be the goblin waiting on the other side when my buddy opens the door, or it could never trigger because the door remains closed the entire round.
You cannot ready full attack actions, but you can ready move actions (providing you haven't already taken a 5' step, since you can't normally move and take a 5' step). You cannot take a standard action (attack someone) and then ready a standard action to attack him again. You cannot ready an action for overly specific or drawn out situations ("I ready an action to shoot the first person through the door but only if he doesn't know the password after three tries").
Often it is used for things like "I'm going to shoot the wizard in the face if he starts casting any spell" or "I will move away from the fighter if he comes within 10 feet of me" or "I will attack the next badguy through the door".
The GM gets to decide what is an acceptable trigger and how to adjudicate the trigger (if the player says 'shoot next thing through the door' and it is his buddy Tom, then technically Tom gets shot because the player wasn't very specific).
Finally, you cannot ready an action outside of combat. You cannot stand in a room and say "I ready an action to shoot any goblin that jumps out in surprise" because there are no goblins yet, so there is no combat yet.