1) The word "oxygen" contains two vowels: O and E.

2) The word "guitar" contains three vowels: U, A, and I.

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) The development of the World Wide Web Consortium (W3C) and web standards has ensured interoperability and compatibility across different web browsers and devices.