Solar.
Coal is the most abundant in the USA
The sun
Geothermal
hydro electric power
Now Romania hasn't an abundant source of energy.
The most abundant source of energy on Earth is solar energy. The Sun continuously radiates vast amounts of energy, which can be harnessed through technologies such as solar panels to generate electricity and heat for various applications.
Romania has energy resources but not so abundant.
The sun is the most abundant energy source that can be harnessed by humans. Solar energy is renewable, clean, and can be captured using various technologies like solar panels to generate electricity for homes and businesses.
Solar.
nuclear
The most abundant source of energy in a muscle fiber is adenosine triphosphate (ATP), which is used to power muscle contractions. ATP is generated through processes like glycolysis and oxidative phosphorylation in the mitochondria.
Solar energy is the most abundant alternative energy source, as the sun provides more energy in one hour than the entire world consumes in a year. Solar panels can harness this energy and convert it into electricity for various applications.