Relative age is the rock’s age compared to the other rocks. In measuring the relative age of rocks, geologists examine the sedimentary rock layers use the law of superposition. According to the law of superposition, youngest rock layers are positioned at the top and older ones are at the bottom. In this case, fossils that are found at the top rock layers are younger than the ones found at the bottom. This method allows the scientists to arrange the fossils records in order according to how organisms have evolved or changed over time.

C. Fossil evidence provides a complete record of the organisms that once lived and are ancestors to other organisms.

After a mass extinction, the population would grow rapidly. The reason for this event was due to the fact that the carrying capacity of a particular ecosystem would increase since there were only a few species competing for resources and there were more ecological roles or niches available for new species. Eventually, the groups that have survived would evolve quickly and this event would lead to the restoration of biodiversity and balance in a particular ecosystem.

A. Species that survive mass extinctions adapt rapidly because they face limited competition.

The Earth’s atmosphere would be different if prokaryotes did not evolve into photosynthetic organisms. Since oxygen is one of the end products of photosynthesis, the oxygen content in the atmosphere increased and life began on Earth. Because of this change, the new conditions have helped living beings to sustain their life processes. Without photosynthesis, life would not be possible on Earth.

D. As prokaryotes evolved, Earth’s atmosphere changed from having little oxygen to having enough oxygen to support cellular respiration.