B
because the compound light has the light bulb in it
Your nose and your mouth are both a portal of entry into your body. If you cover one and not the other it defeats the purpose because Bacteria can still enter the system. They are both part of your respiratory system.
Answer:
Earth's outer core is a fluid layer about 2,400 km thick
Explanation:
composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km beneath Earth's surface
Appalachian Mountains are a part of the Lithosphere