Which reason best explains why carbon is able to form macromolecules?

The atom of carbon is able to form macromolecules because it has only four electrons in its outer shell. This is the reason why it can bond with four other carbon atoms. The bonds that it forms with other carbon molecules are very stable.

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na