Large amounts of energy are required to join two atom's nuclei into a single nucleus and, in turn, create a new element. What is the name of the process where two nuclei join to create a new element?A) combining B) elementium C) fission D) fusion

 fusion

Explanation:

Nuclear fission : It is defined as a process which involves the conversion of a heavier nuclei (which is an unstable nuclei) into two or more small nuclei (which is a stable nuclei) along with release of high amounts of energy.

Example: The energy released from the process of nuclear fission which is converted into electrical energy that is used in our homes and factories.

Nuclear fusion : It is defined as a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.

Example: It occurs in sun and stars where the isotopes of hydrogen called as  Tritium and Deuterium combine together to form a neutron and a helium atom.