part 1: is; part 2: has been observing; part 3: studying; part 4: involves; part 5: have made; part 6: brings; part 7: include; part 8: has; part 9: shows; part 10: play; part 11: is; part 12: live; part 13: is actively fighting; part 14: is becoming; part 15: is flying; part 16: has also engaged; part 17: have been carrying; part 18: has found; part 19: have been contributing; part 20: does not explain; part 21: does not refute; part 22: are extremely