Pls help me out on number 4 and 6 vid; Chemical Reactions that Changed History

Explain in detail of the four major scientific developments that spurred the formulation of the plate tectonics theory

Question 3(multiple choice worth 4 points) (04.04 lc) what does it mean when an element is reduced? it empties a valance shell, reducing its atomic radius. it gains electrons, reducing its overall charge. it increases electronegativity, reducing its ability to bond. it loses electrons, reducing its electron number.

What conclusion can you draw from this experiment about the components of the black ink?