Strength
Strength increases melee damage and inventory space. The Skills & Upgrades guide says each point adds three inventory spaces and notes that Strength also determines whether the character can use the heaviest armor and a couple of the largest weapons.
How it works
The guide presents Strength as more useful to Marines who carry varied weapons and ammunition, and less useful to OSA agents who carry fewer weapon types. These are guide evaluations, not prerequisites or a universal allocation rule.
Read the supporting references
Character attributes, technical skills, combat weapon skills, and operating-system upgrades supported by the supplied System Shock 2 reference windows. Guidance explains the referenced mechanics; it is not a tested damage ranking. Check the stated edition and source version before applying a patch-specific detail.