The research project on climate change (6)___(undertake) by a team of scientists from various disciplines. Each researcher (7)___ (bring) their unique expertise to the project. Over the years, the team (8)___ (collect) an extensive dataset, which (9)___ (analyze) to understand the complex interactions between different climate variables.

Explanation: The verb is for the action (6) - (undertake). The sentence is: 'The research project on climate change (6) (undertake) by a team of scientists...' The structure '...by a team of scientists' indicates the **Passive Voice**. The research project is the subject being acted upon (undertaken). A suitable past passive form is the **Simple Past Passive**: **was undertaken**.