A - 

AEGIS Cruisers - These warships are only effective when the other civilizations have the ability to produce submarines.  AEGIS Cruisers can see submarines within two squares of it and are useful in protecting fleets and your coastline.  Otherwise, the Battleship is a more effect warship as it is stronger in attack, defense, and bombardment, and it is well worth the extra 40 shields to produce.  AEGIS Cruisers also have a Zone of Control, discussed in the Game Concepts part of this site.

Requires:  Robotics, Aluminum, Uranium

Cost:  160 Shields

Stats

Attack:  12        Bombard:  4

Defense:  10        Range:  2

Movement:  5        Rate of Fire:  2

Archer - Archers will help in the early defense of your civilization.  They are cheap so they can be produced quickly.  If defense is a main concern, research Bronze Working and Iron Working to be able to create a Swordsman.

Requires:  Warrior Code

Cost:  20 Shields

Stats

Attack:  2        Defense:  1        Movement:  1

Army - A huge advantage when fighting forces more or equally advanced as yours.  If you have a huge technical gain, your tanks fighting their spearmen, it's just a waste because you probably won't lose even a single unit.  Load up with any mixture of units, however, the entire army will only move as fast as it's slowest unit.  If you want a fast army, you won't want to put any units with 1 movement point with Horse or other fast units.  Also, the attack and defense value is an average of the units in the army.  The Hit points are simply added together.  Example:  An army is made up of Regular Cavalry, a Regular Swordsman, and a Veteran Marine. The attack values of these units are 6, 3, and 8 respectively.  The average attack is 5.66, so the attack value of the army is 6.  The defense values are 3, 2, and 6 respectively.  The average defense is 3.66, so the defense value is 4.  The slowest unit in the army is the Swordsman, 1, so the movement of the army is 1.  The Hit points are 3, 3, and 4.  Therefore, the stats of this example army is (10/10)(6.4.1).  This allows you to customize your army to have what ever stats you want.  Remember that bombardment units, artillery, sea, or air units can't be in an army.  Also units can upgrade, and add hit points to the army, when victorious, so you don't necessarily have to load in all elite units at the beginning to have a 15 Hit point army.  To make an army, you must have a Leader to enter your city, and build an army, and then load the army with units of your choice  Once an army is victorious, building the Military Academy Small Wonder will allow you to build armies at that city only, at a hefty cost of 400 shields.  Tip:  Build this in a city with high shield production.

Artillery - Upgrades from Cannon.  It is the first bombardment unit with a range of 2, and is useful for an offensive push or defending cities.