Question

Scientists around the world have been working for decades on perfecting the process of nuclear fusion in the lab. Which statement justifies this research?
Scientists are looking for a way to generate an unlimited source of hydrogen.
Scientists are looking for a way to absorb the energy produced by nuclear bombs.
Scientists are looking for a way to produce the uncommon noble gas helium.
Scientists are looking for a way to create cheap, safe, and sustainable energy.

Answer 1

Scientists are looking for a way to create cheap, safe, and sustainable energy.

Nuclear fusion is the process by which two atoms rapidly collide at each other forming a new nucleus. The energy of colliding and synthesizing has intrigued scientist into believing that this could be one of best sources of renewable energy. 

Answer 2

The reason why scientists around the world have been working for decades on perfecting the process of nuclear fusion in the lab is because they want to produce a way of creating cheap, safe, and sustainable energy - D. This is also what nuclear fusion would bring us eventually.