Question

in the 1930s, germany first began to expand aggressively by joining german forces with italy. rebuilding the german military. making a pact with china. invading russia.

Explanation:

In the 1930s, Germany first started its aggressive expansion by rebuilding its military in violation of the Treaty of Versailles. This was a key step in its path to war. Joining with Italy happened later and was more of an alliance - building move. Making a pact with China was not part of its early - expansion moves. Invading Russia occurred in 1941, which is later than the early 1930s.

Answer:

rebuilding the German military.