What components do you lose when your pneumatics are closed?

When the pneumatics are closed, the correct components that are lost include engine starts, packs, pressurization, and anti-ice systems. This is because pneumatic systems are crucial for supplying compressed air for various functions in an aircraft. During engine starts, pneumatic pressure is needed to help ignite the fuel mixture and promote combustion. The packs, which are responsible for air conditioning and pressurization within the cabin, rely on pneumatic pressure to function properly. Additionally, the anti-ice systems, which prevent ice buildup on wings and engine components, also utilize pneumatic pressure for their operation.

In this scenario, the other options mention systems that are either operated by different means or are not directly affected by the closure of the pneumatic system. Flaps and landing gear systems, for example, primarily rely on hydraulic power, while cabin pressure and oxygen supply involve separate systems distinct from pneumatic operations. Control surfaces and hydraulic systems are also managed through hydraulic systems rather than pneumatic pressure. Thus, the comprehensive loss of engine starts, packs, pressurization, and anti-ice functions clearly illustrates the critical nature of pneumatic systems in aircraft operations.