Final answer:
Natural gas and hydropower are significant contributors to the world's electricity production. While wind power's contribution is increasing, it is less compared to natural gas and hydropower. Solar photovoltaic and biofuels contribute a smaller percentage to the global electricity mix.
Step-by-step explanation:
Among the sources listed, natural gas and hydropower significantly contribute to the world's electricity production. Data indicates that natural gas, along with burning coal, is a primary source of global electricity generation. Hydropower, which harnesses the energy of moving water to generate electricity, has been a longstanding contributor, although it has been overshadowed by fossil fuels like coal and natural gas in many areas. Wind power has also made substantial strides and now represents a more significant portion of the world's electricity production compared to earlier times, although it still lags behind fossil fuels and hydropower. The growth of solar photovoltaic panels has been impressive, yet it constitutes a smaller percentage of global electricity compared to natural gas and hydropower. Biofuels, even with advancements, contribute less significantly to the electricity mix when compared to natural gas or hydropower.
It's important to note that while solar and wind power have seen exponential growth in recent years, the current global energy mix continues to be dominated by fossil fuels. This dominance is reflected in the percentage contributions of different energy sources to global electricity production, with renewable energy sources such as solar and wind power still occupying a relatively small, albeit growing, share of the overall energy portfolio. Nuclear power, not listed among the options, also accounts for a meaningful percentage of global electricity generation without direct CO2 emissions.