At the start of the war, which countries were on the side of the central powers? check all that apply.
ottoman empire
great britain
russia
austria-hungary
italy

Austria-Hungary, and the Ottoman Empire

Explanation:

Austria-Hungary was one of the main antagonists of the war, and the Ottoman Empire joined after forming a secret alliance with Germany in August of 1914.

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.