Based on the clue 'about 25 of the more than 250 species of these are...', what is the answer?

Based on the clue 'about 23 of the weight of bone tissue consists of ...', what is the answer? Based on the clue 'about 23 of this rivers 23 million square mile tro...', what is the answer? What is associated with: about 230 years bs before shakespeare chaucer wrote an 8000 line poem about this title homeric… Based on the clue 'about 25 miles north of miami it was named for a s...', what is the answer? What is associated with: about 25 people were arrested under this group of 4 acts passed in 1798 all were repealed or e… What is associated with: about 25 species of this arachnid most in the family buthidae have venom thatll kill you 1200… Based on the clue 'about 250 miles long this river is usually navigab...', what is the answer? Based on the clue 'about 250 of these 2 named western us vultures sur...', what is the answer?