A team of scientists are studying three different layers of sedimentary rock to learn about a particular reptile species. In the
layer of rock that is closest to the Earth's surface, the reptiles' teeth fossils are found to be short and straight. In the layer below, the reptiles' teeth fossils are found to be long and straight. In the layer below that, the reptiles' teeth fossils are found to be long and curved. Based on this information, the reptiles today most likely have
<u>Sedimentary rock forms in layers over time. As time passes, new layers form upon the older layers. This means that as time passes, fossils are buried deeper and deeper in the ground. Therefore, fossils found in higher layers of sedimentary rock are newer than fossils found in lower layers of sedimentary rock.
</u>
<u></u>
<u>Since the layer of sedimentary rock that is closest to the Earth's surface contains short, straight teeth fossils, the reptile species is most likely to have short, straight teeth today.
</u>
Saliva's normal pH range is between 6.2 and 7.6. It's average is like a 6.7. Saliva keeps a neutral pH balance and doesn't fall below 6.3 in the oral cavity.
