Trong tự nhiên có hai đơn vị bền của của C là 12C và 13C . Nguyên tử khối trung bình là 12,011. Phần trăm về khối lượng của 13C trong tự nhiên là

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?