How is a fossil record evidence for evolution

Fossils are the dead remnants of ancients flora and fauna that are buried millions of years ago. These fossils are found to be present in the sedimentary rocks. These fossils are very important in order to understand the evolutionary pattern of the organisms, their food habitat and also the past climatic and environmental conditions.

These fossils play a key role in determining the way the organisms have undergone evolution. The earliest fossil found on earth belongs to the rocks of Western Australia that dates back to about 3.5 billion years. The fossils belonging to the pre-historical time were very simple, and the fossils that belong to the recent ages are very complex. This marks the pattern of how evolution has taken place. The earth has experienced episodic mass extinction events that wiped out more than 90% of the living species on earth, but only those organisms survived which were able to adapt to the changing environmental conditions.

These organisms have undergone evolution with the gradual increase in time, forming more, new and complex types of living species. Some of the fossils are also found that records the entire evolution pattern. For example, the evolutionary pattern of the horse has a complete record.

i think its both a and b

i think the answer would be a. after sentence 14! i hope i at least a little