Which of the following activities has a negative impact on biodiversity

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.

Explain the source of radioactivity in uranium in earth’s crust by which it produces nuclear radiation

Which description provides the best objective summary of the article in the passage?