A student is riding the bus to school. As he rides, he studies a worksheet for a quiz while listening to music on his smartphone. Once he arrives at school, he sits at his desk in homeroom. Which resource in the scenario is renewable?

the diesel used to fuel the bus
the paper used to print the work sheet
the aluminum used to make the desk
the plastic used to make the smartphoneHow many atoms of oxygen in the chemical formula 2Ca(ClO2)2?

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.  

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.