What rule applies to this word? exhaust
Group I. If the root is a full word, the ending is usually -able.
Group II. When the root is a full word except for a final e, the forms usually are spelled with -able.
O Group III. The suffix -able always follows i.
Group IV. When the root has other forms built on the letter a, the -able form is used.
O Group V. When the root ends in hard c or hard g, -able is used.
O Group VI. When the root is not a full word,-ible is used.
O Group VII. When the word has an immediate -tion form, -ible is used.
Group VIII. When the root ends in ns, miss, or soft cor g, ible is used.

(1) fire extended humans’ geographical boundaries by allowing them to travel into regions that were previously too cold to explore. (2) it also kept predators away, allowing early humans to sleep securely. (3) fire, in fact, has been a significant factor in human development and progress in many ways. (4) other obvious benefits of fire are its uses in cooking and in hunting. (5) probably even more important, however, is that learning to control fire allowed people to change the very rhythm of their lives. (6) before fire, the human daily cycle coincided with the rising and setting of the sun. (7) with fire, though, humans gained time to think and talk about the day’s events and to prepare strategies for coping with tomorrow. the sentence that expresses the main idea is: (type the number of the sentence. then click “go.”)

Dogs make wonderful pets because they us stay happy and healthy. the topic sentence is "dogs make wonderful pets." , is this correct? i keep doubting myself.

The_of a story can be applied to other works of literature or to life.