Which factors add to the greenhouse effect and are caused by human activities? Select two options.

a decrease in the amount of dust in the atmosphere
a decrease in the amount of water on Earth’s surface
an increase in gases in the atmosphere that absorb heat
an increase in surfaces that radiate energy into the atmosphere
an increase in the amount of solar radiation that reflects into space

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.