Answer: D) helium.
Explanation:
Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.

Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.
Example: 
Thus when deuterium and tritium , the two isotopes of hydrogen are fused, a heavier nuclei helium is being formed from two smaller nuclei releasing a neutron.
Answer:
one of the atoms sharing electrons is more electronegative than the other atom
Explanation:
Titanium has an atomic number of 22, which means it has 22 protons and 22 electrons. About 73.8 percent of natural titanium exists as the isotope Ti-48, which contains 26 neutrons.