In the following passage, some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each blank.
Comprehension:
The first human beings to control fire gradually learned (1)______ many uses. Not only did they (2)______ fire to keep warm and cook their food; they (3)______ learned to use it in hunting or warfare, to kill insects, to (4)______ berries, and to clear forests of underbrush so that game (5)______ be better seen and hunted. Eventually they learned that the burning of brush produced better grasslands and therefore more game.