Match the scientist with their key contribution to understanding photosynthesis.
| Column I | Column II |
|---|---|
| (a) Joseph Priestley | (i) Showed that sunlight is essential to the plant process |
| (b) Jan Ingenhousz | (ii) Discovered oxygen and its role in restoring air |
| (c) T.W. Engelmann | (iii) Inferred that Oâ‚‚ comes from Hâ‚‚O, not COâ‚‚ |
| (d) Cornelius van Niel | (iv) Described the first action spectrum of photosynthesis |