The Battle of Antietam <span>led to the Emancipation Proclamation.</span>
B. The rivers were used to sustain life by growing crops and food and having an unlimited drinking supply.
A. at the same time that Earth formed
Explanation:
Geologists think the earth's continents began to form about the same time the earth was formed.
Most of the rocks on the continental crust are about the oldest that been used to date the age of our planet.
- Oceanic plates are relatively very young as they are formed at spreading centers and destroyed at convergent margins.
- Continental masses have very high absolute ages.
- The oldest rock on earth such as the Kabala Gneiss have been dated to be about 3 billion years.
- Other rocks have yielded ages close to the formation of the earth.
- We can conclude that the continents began to form immediately after the earth was formed.
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Answer:
the fossil organisms lived for only a short span of geologic time
Explanation:
The index fossils are very useful when it comes to determining the relative age of the rock layers, as well as the other fossils found in the same layer with them. These fossils have four basic characteristics, they appear only in limited geologic time, they are widespread, abundant, and distinctive. The fact that they are limited in their geologic existence is very good for the geologists as when they find a fossil like this they are immediately aware of the geologic period they are working with without having to make examinations. Also, these fossils can be found in abundance and in numerous places around the world, thus the same fossil can be used as a time scale almost everywhere. Being distinctive also helps a lot because the geologist can immediately be aware of the type of organism without having to further examine it.
Because<span> the surrounding </span>mountains<span> contain very little soil, and nutrients are easily washed into </span>the lakes<span>, which could cause algae blooms
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