To promote the growth of vegetation, aborigines
a.
used fire to do controlled burns
b.
developed new types of fertilizer
c.
practiced animism
d.
let sheep graze only in certain areas

A. Used fire to do controlled burns

The result of  controlled burns were highly beneficial to both the Aborigines and the environment. The burnt remains of the burns were very fertile and encouraged the growth of new vegetation that would not have been able to flourish if the older growth had not been removed. The removal of old vegetation also resulted in a low chance of wild fires. Further more new vegetation was able to attract wildlife to graze, making hunting easier. 

The concept of controlled burns is still used today and was/is also practiced by First Nations in North America.

The answer is b im not sure