Austin lives in our community that is looking for more ways to reduce the human impact of the environment which of the following human activities is most likely to result in the greatest change in the vegetation of a region

the answers would be

the first one and the second one

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.