1) The United States operates under a two-party system, with the Democratic Party and the Republican Party being the two major political parties that compete in elections and shape the country's political landscape.

2) The ozone layer, located in the Earth's stratosphere, protects us from harmful ultraviolet (UV) radiation.

3) Chocolate chip cookies, a beloved sweet treat, were invented by Ruth Graves Wakefield in the 1930s. Wakefield ran the Toll House Inn in Massachusetts and added chopped chocolate to her cookie dough, expecting it to melt and create an all-chocolate cookie. Instead, the chocolate bits retained their shape, giving birth to the classic chocolate chip cookie. Today, they are a staple in cookie jars, dessert menus, and homemade baking, enjoyed by people of all ages.

4) A newborn kangaroo is about 1 inch (2.5 centimeters) long and weighs less than a gram.