Questions

The Doppler effect or Doppler shift is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. 

394  is the code to unlock the key.

If you take the second statement, 7 is incorrect from the first statement and 1 is incorrect from the fourth statement. Hence 4 is correct, but not on the second place. From the third statement, 4 is not on the first place. Hence 4 is on the third place.

From the fifth statement either 6 or 9 is correct. But combining it with the third statement, 6 is incorrect. Hence along with the first statement, 9 is correct and on the second place.

From the third statement, 3 is correct and on the remaining first place.

If we read the question clearly twice, we can understand that the name of the horse on which the cowboy rides into town is FRIDAY.

Expedite means making an action fast or sooner i.e, to accomplish a work as quickly as possible.

Hence, halt means stop and it is opposite of Expedite.

Inhabit means a place or environment to live in for a person or animal or a group.

Vacate, move and reside means to leave a place and are opposite to live. Reside is the only word most nearly means as inhabit.