पृथ्वी के आंतरिक भाग की किस परत को एस्थेनोस्फीयर (दुर्बलतामंडल) के रूप में जाना जाता है?

Which of the following terms is historically used to refer to the innermost layer or the core of the Earth?

The Earth's mantle extends from the base of the crust down to a depth of approximately ______.

Which of the following metals is the most abundant in the Earth's crust?