Answer:
radiometric dating
Explanation:
Some minerals in rocks and organic matter for example bones and shells can contain radioactive isotopes. Any of parent and daughter isotopes in a sample can be measured and used to determine their age. This is known as radiometric dating.
Answer: Cuestan.
Explanation: Cuanto means How much in english, so the question is asking how much those books are going to cost. Whenever you see a Cuanto in a question like that, assume it's talking about a number of something, or money. So Cuestan means cost, in the terms of "How much does this item cost?".
20. Mira
21. Haz
22. Ponte
