Answer: Carbon
Explanation:Carbon is the element released by volcanic outgassing,animal respiration and flatulence,burning of fossil fuels and the metamorphism of limestone.
Volcanic outgassing is the release of carbon into the atmosphere mainly in the form of carbon monoxide.
Animal respiration and flatulence are process taking place in animals which leads to the release of carbon dioxide.
Burning of fossil fuels is the use of heat to breakdown fossil fuels such as petroleum leading to the release of Carbon.
Limestone metamorphism is the breakdown of limestone which leads to the release of Carbon to the atmosphere.
 
        
             
        
        
        
The statement "Mass extinctions have occurred several times on Earth" explains the indication of the fossil record. 
<h3>Indication of Fossil fuels:</h3>
Paleontologists are fascinated by the evolution and extinction of fossil species throughout geologic history. To do so, they look at all the fossils that have been preserved in sedimentary rocks. 
The fossil record is what we call it. Paleontologists have been collecting fossils from sedimentary rock layers all over the world for over two centuries. 
Their goal is to figure out how species have evolved over geologic time. It can be used as a geologic timescale once the succession is established. 
Then, if a specific fossil is discovered in a rock, you can determine where it belongs on the geologic timescale. 
Therefore, the correct option is the third sentence. 
Learn more about fossil fuel here:
brainly.com/question/13655515