How does the speaker know that the lump of metal she is holding is an asteroid

The patterns formed inside the metal

Explanation:

Carrie Nugent talks about an asteroid in this Ted Talk.

She explains that the rock is older the earth and that it is an asteroid due to the patterns formed inside it that show it contains metallic crystals that cannot be formed on earth but in space where temperatures mean that molten metal takes billions of years to cool.

iii. and iv. only is the right answer

answer; the correct answer to the above statement is (biosphere); ///