In an experiment, what variable does the experimenter observe as a result of the changing independent variable

controlled variable
dependent variable
independent variable
hypothesis

the answer is a for sure mark brainliest i had got this right on usatestprep

d

explanation:

answer carbon and three oxygen atoms;

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.