1) The largest living structure on Earth is the Great Barrier Reef, spanning over 2,300 kilometers (1,400 miles) along the coast of Australia.

2) The longest English word is "pneumonoultramicroscopicsilicovolcanoconiosis," which refers to a lung disease caused by inhaling very fine silica dust.

3) The term "bull market" refers to a period of rising stock prices, while a "bear market" refers to a period of falling stock prices.

4) The word "pencil" contains two vowels: E and I.