1) In Norse mythology, the Valkyries are divine maidens who serve Odin, the chief god. They are responsible for selecting warriors worthy of entering Valhalla and escorting them to the afterlife. They are often depicted as powerful and beautiful figures, riding winged horses and wielding spears.

2) DNA, the building block of life, can store incredible amounts of data. It is estimated that one gram of DNA could potentially store about 215 petabytes of data.

3) The word "triangle" contains four vowels: I, A, E, and E.

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.