Question

rising tensions
the widespread growth of standing armies was one factor that led to world war i. this is called
when two countries agree to fight alongside one another, they have a(n)
dependency
alliance
escalation

Explanation:

First Blank (The widespread growth of standing armies...):

The widespread growth of standing armies before World War I is known as "militarism". But since the first blank's options aren't shown, for the second blank: when two countries agree to fight alongside each other, the term is "alliance" (dependency is a relationship of reliance, escalation is increasing tension/conflict, alliance is a partnership in war).

Answer:

Second blank: alliance (from the options: dependency, alliance, escalation)