A dog sled driver prepared for a race. Her sled is being loaded with equipment but on snow and ice, the dogs moved the heavy sled. During the race, she came to an area of grass and dirt instead of snow. The sled came to a stop. The sled driver said, "There must be something wrong with a dog One of them is now pulling with a force of 600N." How would you respond to the driver? (THIS QUESTION IS BASED ON FRICTION)

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.