I want to know the answer to the following question:
What churches have been strongly engaged in the ecumenical movement?
All the background I'm provided with is that "There has been a strong engagement of Orthodox churches in the ecumenical movement, though the reaction of individual Orthodox theologians has ranged from tentative approval of the aim of Christian unity to outright condemnation of the perceived effect of watering down Orthodox doctrine.". Is that enough to answer the question?
Answer: yes