1) The Black Lives Matter movement gained renewed momentum in 2020 following the killings of George Floyd, Breonna Taylor, and others, sparking protests and discussions on systemic racism, police reform, and social justice around the world.

2) The word "mountain" contains three vowels: O, U, and A.

3) The first computer mouse was invented by Douglas Engelbart in 1964 and consisted of a wooden shell and two metal wheels.

4) The word "book" contains two vowels: O and O.