1) The process of nuclear fusion powers the sun and other stars, fusing hydrogen atoms together to form helium and releasing vast amounts of energy in the process.

2) The Internet of Things (IoT) refers to the network of physical devices, vehicles, appliances, and other objects embedded with sensors, software, and connectivity.

3) The United States recently held its presidential election in 2020, resulting in Joe Biden being elected as the 46th President of the United States and Kamala Harris as the Vice President, making history as the first female Vice President.

4) The hamburger, consisting of a ground beef patty served between two buns, is an iconic American food. It has gained global popularity and countless variations, from classic cheeseburgers to gourmet creations with unique toppings and sauces. The invention of the hamburger is often attributed to Louis Lassen, a Danish immigrant in Connecticut, who served the first hamburger in the early 20th century. Today, hamburgers are a staple in fast-food chains, casual diners, and backyard barbecues around the world.