If you use your combat bonus, that says: 'add 3 to the strength of its attack', do you increase the attack only, or also the health points?
Strength of attack
attack only
Following on from this question, does the strength bonus contribute to determine the victor of the battle?
The victor of battle is decided by health remaining plus the combat bonus granted from barracks, shipyard, great general, academy, etc. So no, the extra strength granted from a resource ability does not count toward deciding the victor of the battle.