1) The Eiffel Tower can be 15 cm taller during the summer due to thermal expansion.

2) 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.

3) The word "pizza" contains two vowels: I and A.

4) The COVID-19 pandemic has highlighted the importance of global collaboration and solidarity in addressing public health emergencies, with efforts focused on vaccine sharing, equitable distribution, and support for developing countries.