Which of the following do fossils represent and what do they tell us?
a. extant species that tell the story of human origins
b. extinct organisms that provide a record of the history of life on the planet
c. plants that provide proof of catastrophism
d. organisms that demonstrate the age of the Earth through the process of uniformitarianism

b. extinct organisms that provide a record of the history of life on the planet

Explanation:

Fossil are preserved remains or traces of organism that once existed in the past geologic period. These organisms might leave remains of their hard parts like tooth or bones. Discovering these bones or tooth gives more information on the history of past life on the planet earth. Impression left by soft parts like the leaf vein can also be use to provide history of life on earth.

Most fossils are usually remains of extinct organisms, that is organism that once lived in the earth. Organism activities such as burrowing made by small organism can serve as a fossil record too. Studying these traces provide more information of life on earth.

For Fossilization to occur it requires some criteria or condition for it to occur. These includes rapid and permanent burial to avoid loss of the body parts, Lack of oxygen to prevent  rapid decay of the organism part and the absence of heat to limit  destruction of the body parts.