Question

which layer of earth reaches a depth of about 4,000 km and contains liquid iron and nickel? mantle outer core inner core lithosphere

Explanation:

The Earth's layers have distinct characteristics. The mantle is solid (though can flow slowly over time). The lithosphere is the rigid outer layer. The inner core is solid due to extreme pressure. The outer core, at a depth reaching about 4000 km, is liquid and composed mainly of iron and nickel.

Answer:

Outer Core