It could be, for example, the risk of a change in the economic environment _ what are your contingency plans for that in terms of dealing with such a situation? There may be many other risks as well specific to your particular sphere of operation, but that ability to plan ahead for all scenarios makes for a robust business plan. When I have received business plans, the very best responses come from people who have looked at the risks and have an answer for every question. What you never want is to throw a scenario at your plan and have to answer "I don't know what I would do in that situation". You want to plan for every possible contingency, and certainly all the major risks to the ongoing success of your business.
Labor and material costs are also directly proportionate to sales. These are things that go directly into the making of the product or into doing the service. a. Labor cost is the actual direct labor used in the making of product or doing the service. The cost would also include all the fringe benefits like social security, payroll taxes, vacation pay, holidays, sick pay days, etc. b. Material costs are all the materials used in the making of product or in doing the service. In the lawn mower service as an example it would be the gasoline used in the mower and any other materials used directly in that service. For producing a product it would be all the materials used in the product that is sent to the customer including all the packaging materials.