Answer:
Bone
Explanation:
Even though they are made of tissue they are not primary.
The atmosphere is divided into different regions, called layers. The layer closest to the surface is known as troposphere, after which comes the stratosphere. The stratosphere begins at an altitude of 10 miles above the surface of the earth and stretches up to 31 miles above the surface of the earth. It is the second layer of the atmosphere (beginning from the surface of the earth) and it is the region which contains ozone, which plays a vital role in stopping ultraviolet radiation from reaching the earth's surface.
Stable isotopes refers to those isotopes that do not undergo radioactive decay. Oxygen atoms with atomic number of 16 and 18 are examples of stable isotopes. These isotopes of oxygen are usually found in substances such as polar ice and calcite. These substances are usaually measure with isotope fractionation and the ratios obtained are used to estimate water temperature of ancient oceans. From this, scientists can find out facts about ancient climates,
