1) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

2) The Amazon rainforest produces more than 20% of the world's oxygen.

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

4) The painting "The Scream" by Edvard Munch is an iconic work of art that depicts a figure in anguish and has become a symbol of existential angst.