What do we call any consumable required to accomplish an activity, which may include time, monetary, human, and physical investments?

The term used for any consumable required to accomplish an activity, encompassing time, monetary, human, and physical investments, is "resources." Resources are integral to project management and cost estimation, as they represent all inputs necessary for carrying out tasks or activities. This includes not only materials but also labor, equipment, and financial resources that contribute to achieving project objectives.

Assets pertain to valuable items owned by an organization, which do not necessarily include consumables needed for specific activities. Liabilities reflect obligations or debts owed by the organization, rather than inputs or consumables for tasks. Materials specifically refer to tangible items needed for construction or production, which is a subset of the broader category of resources. Therefore, "resources" is the most comprehensive and appropriate choice in the context of this question, as it captures all types of consumables necessary for completing activities.