1) The development of the microprocessor by Intel in 1971 paved the way for the modern computer and led to the exponential growth of computing power.

2) The Northern Lights, also known as the Aurora Borealis, are natural light displays that occur in the polar regions due to interactions between the Earth's magnetic field and solar particles.

3) The political system of the People's Republic of China is based on the Communist Party's leadership, with the General Secretary holding significant authority and influence over the country's policies and governance.

4) The concept of federalism involves the division of powers between a central government and regional or local governments, allowing for shared governance and autonomy for different levels of administration.