Which of the following procedures is used when refining petroleum? decrease the pressure of the oil
increase the pressure of the oil
decrease the temperature of the oil
increase the temperature of the oil

increase the temperature of the oil

Explanation:

One of the ways petroleum is refined by increasing the temperature of the oil. This process is known as thermal cracking.

  Thermal cracking is the process by which petroleum or crude-oil is subjected to high temperature to break down their long chains.

Increase the temperature

Explanation:

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.