The phase(s) of matter that demonstrate fluidity include:

Liquid and Gas are the phases of matter that demonstrate fluidity.

Explanation:

The phenomenon of easy flow or easy transfer or movement of particles is termed as fluidity. As it is known that matters are basically classified into three types or phases. They are solid, liquid and gases. The solid particles are tightly bonded. In other words, high energy is required to move the atoms in the solid material. But in liquid the atoms are slightly loosely bonded. So they are flow easily. With only the viscous tendency hindering its flow, the liquid phased materials can be termed as fluid. Similarly, the easiest travelling particles are gas particles and so they also have fluidity and they are also termed as fluid. So the phases which are termed under fluid criteria demonstrating fluidity included liquid and gas phase

it is the most commonly accepted one

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.