English

The majority of the time fossils are dated using relative dating techniques. Using relative dating the fossil is compared to something for which an age is already known.
For example, if you have a fossil trilobite and it was found in the Wheeler Formation. The Wheeler Formation has been previously dated to approximately 507-million-year-old, so we know the trilobite is also about 507 million years old.
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation. Index fossils are fossils that are known to only occur within a very specific age range. Typically, commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites work best as index fossils. If the fossil you are trying to date occurs alongside one of these index fossils, then the fossil you are dating must fall into the age range of the index fossil.
Sometimes multiple index fossils can be used. In a hypothetical example, a rock formation contains fossils of a type of brachiopod known to occur between 410 and 420 million years. The same rock formation also contains a type of trilobite that was known to live 415 to 425 million years ago. Since the rock formation contains both types of fossils the age of the rock formation must be in the overlapping date range of 415 to 420 million years.
Studying the layers of rock or strata can also be useful. Layers of rock are deposited sequentially. If a layer of rock containing the fossil is higher up in the sequence that another layer, you know that layer must be younger in age. If it is lower in sequence it's of a younger age. This can often be complicated by the fact that geological forces can cause faulting and tilting of rocks.
Unlike relative dating method absolute dating which is used to determine a precise age of a rock or fossil through radiometric dating methods. This uses radioactive minerals that occur in rocks and fossils almost like a geological clock. It's often much easier to date volcanic rocks than the fossils themselves or the sedimentary rocks they are found in. So, often layers of volcanic rocks above and below the layers containing fossils can be dated to provide a date range for the fossil containing rocks.
The atoms in some chemical elements have different forms, called isotopes. These isotopes break down at a constant rate over time through radioactive decay. By measuring the ratio of the amount of the original (parent) isotope to the amount of the (daughter) isotopes that it breaks down into an age can be determined.
We define the rate of this radioactive decay in half-lives. If a radioactive isotope is said to have a half-life of 5,000 years that means after 5,000 years exactly half of it will have decayed from the parent isotope into the daughter isotopes. Then after another 5,000 years half of the remaining parent isotope will have decayed.
While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils. Carbon-14, the radioactive isotope of carbon used in carbon dating has a half-life of 5730 years, so it decays too fast. It can only be used to date fossils younger than about 75,000 years. Potassium-40 on the other hand has a half like of 1.25 billion years and is common in rocks and minerals. This makes it ideal for dating much older rocks and fossils.

All of the following can be inferred abouAbsolute dating is used to determine a precise age of a fossil.
B. It uses radiometric dating to measure the decay of isotopes.
C. It compares similar rocks and fossils of known ages.
D. Volcanic rocks are much easily dated by this method.

t absolute dating EXCEPT

Most North Americans think minimal about American Indian culture and history. Researchers have concentrated such issues, yet they have not succeeded in broadcasting their decisions generally. Subsequently, it is as yet not generally realized that American Indians have epics, that they performed plays sometime before Europeans showed up, and that they practised politics and carried on the exchange system.

One way to gain a fuller appreciation of this rich culture is to examine American Indian poetry, for poetry is in all cultures the most central and articulate of the arts. It is especially important that we study American Indian poetry as this poetry can create a context that gives cohesive expression to the crafts, the artifacts, and the isolated facts that many Americans have managed to notice willy-nilly. Even a survey of American Indian poetry reveals a range of poetic thought and technique that defies easy generalization. Jarold Ramsey hazards a summary, however, which serves at least to give the uninitiated reader some sense of what American Indian poetry is like. Overall, he writes, it represents “an oral, formulaic, traditional, and anonymous art form,” whose approach is to emphasize the “mythic and sacred” components of reality. It “flourished through public performances. by skilled recitalists whose audiences already knew the individual stories” and valued the performers for their “ability to exploit their material dramatically and to combine them? their stories? in longer cycles” rather than for their “plot invention.” Because this poetry belongs to highly ethnocentric tribal peoples, whose cultures “we still do not know much about,” it “is likely to seem all the terser, even cryptic.”

American Indian poetry has another feature that Ramsey ignores: it is always functional. Whether sung, chanted, or recited; whether performed ceremonially, as entertainment, or as part of a task such as curing a patient or grinding corn; or whether recited individually or by a group, it is always fully woven into the fabric of ordinary life.

For complicated reasons, American Indian poetry has basically been ignored by non-Indian cultures. Kenneth Lincoln writes that failure to hear American Indian voices results “partly.from the tragedies of tribal dislocation, partly from mistranslation, partly from misconceptions about literature, partly from cultural indifference.” Brian Swann suggests an additional explanation: tribal poetry is oral, whereas Europeans arrived in the New World with a deeply ingrained belief in the primacy of the written word. As a result, European settles found it hard to imagine that poetry could exist without written texts and thus that the American Indians had achieved something parallel to what Europeans called literature long before Europeans arrived. As a consequence, Europeans did not fully respond to the rich vitality of American Indian poetry.

Which of the following features of American Indian poetry has NOT got any mentions in the passage?

The four sentences (labelled 1, 2, 3 and 4) below, when properly sequenced, would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and choose the correct option

1. Nelson Mandela was the son of Chief Henry Mandela of the Madiba clan of the Xhosa-speaking Tembu people.

2. Nelson renounced his claim to the chieftainship to become a lawyer.

3. After his father's death, young Nelson was raised by Jongintaba, the regent of the Tembu.

4. He attended South African Native College (later the University of Fort Hare) and studied law at the University of the Witwatersrand; he later passed the qualification exam to become a lawyer.

Most North Americans think minimal about American Indian culture and history. Researchers have concentrated such issues, yet they have not succeeded in broadcasting their decisions generally. Subsequently, it is as yet not generally realized that American Indians have epics, that they performed plays sometime before Europeans showed up, and that they practised politics and carried on the exchange system.

One way to gain a fuller appreciation of this rich culture is to examine American Indian poetry, for poetry is in all cultures the most central and articulate of the arts. It is especially important that we study American Indian poetry as this poetry can create a context that gives cohesive expression to the crafts, the artifacts, and the isolated facts that many Americans have managed to notice willy-nilly. Even a survey of American Indian poetry reveals a range of poetic thought and technique that defies easy generalization. Jarold Ramsey hazards a summary, however, which serves at least to give the uninitiated reader some sense of what American Indian poetry is like. Overall, he writes, it represents “an oral, formulaic, traditional, and anonymous art form,” whose approach is to emphasize the “mythic and sacred” components of reality. It “flourished through public performances. by skilled recitalists whose audiences already knew the individual stories” and valued the performers for their “ability to exploit their material dramatically and to combine them? their stories? in longer cycles” rather than for their “plot invention.” Because this poetry belongs to highly ethnocentric tribal peoples, whose cultures “we still do not know much about,” it “is likely to seem all the terser, even cryptic.”

American Indian poetry has another feature that Ramsey ignores: it is always functional. Whether sung, chanted, or recited; whether performed ceremonially, as entertainment, or as part of a task such as curing a patient or grinding corn; or whether recited individually or by a group, it is always fully woven into the fabric of ordinary life.

For complicated reasons, American Indian poetry has basically been ignored by non-Indian cultures. Kenneth Lincoln writes that failure to hear American Indian voices results “partly.from the tragedies of tribal dislocation, partly from mistranslation, partly from misconceptions about literature, partly from cultural indifference.” Brian Swann suggests an additional explanation: tribal poetry is oral, whereas Europeans arrived in the New World with a deeply ingrained belief in the primacy of the written word. As a result, European settles found it hard to imagine that poetry could exist without written texts and thus that the American Indians had achieved something parallel to what Europeans called literature long before Europeans arrived. As a consequence, Europeans did not fully respond to the rich vitality of American Indian poetry.

Who stated this interpretation “American Indian poetry is an art form characterized by its adaptability to public performance”?

Most North Americans think minimal about American Indian culture and history. Researchers have concentrated such issues, yet they have not succeeded in broadcasting their decisions generally. Subsequently, it is as yet not generally realized that American Indians have epics, that they performed plays sometime before Europeans showed up, and that they practised politics and carried on the exchange system.

One way to gain a fuller appreciation of this rich culture is to examine American Indian poetry, for poetry is in all cultures the most central and articulate of the arts. It is especially important that we study American Indian poetry as this poetry can create a context that gives cohesive expression to the crafts, the artifacts, and the isolated facts that many Americans have managed to notice willy-nilly. Even a survey of American Indian poetry reveals a range of poetic thought and technique that defies easy generalization. Jarold Ramsey hazards a summary, however, which serves at least to give the uninitiated reader some sense of what American Indian poetry is like. Overall, he writes, it represents “an oral, formulaic, traditional, and anonymous art form,” whose approach is to emphasize the “mythic and sacred” components of reality. It “flourished through public performances. by skilled recitalists whose audiences already knew the individual stories” and valued the performers for their “ability to exploit their material dramatically and to combine them? their stories? in longer cycles” rather than for their “plot invention.” Because this poetry belongs to highly ethnocentric tribal peoples, whose cultures “we still do not know much about,” it “is likely to seem all the terser, even cryptic.”

American Indian poetry has another feature that Ramsey ignores: it is always functional. Whether sung, chanted, or recited; whether performed ceremonially, as entertainment, or as part of a task such as curing a patient or grinding corn; or whether recited individually or by a group, it is always fully woven into the fabric of ordinary life.

For complicated reasons, American Indian poetry has basically been ignored by non-Indian cultures. Kenneth Lincoln writes that failure to hear American Indian voices results “partly.from the tragedies of tribal dislocation, partly from mistranslation, partly from misconceptions about literature, partly from cultural indifference.” Brian Swann suggests an additional explanation: tribal poetry is oral, whereas Europeans arrived in the New World with a deeply ingrained belief in the primacy of the written word. As a result, European settles found it hard to imagine that poetry could exist without written texts and thus that the American Indians had achieved something parallel to what Europeans called literature long before Europeans arrived. As a consequence, Europeans did not fully respond to the rich vitality of American Indian poetry.

All of the following can be inferred from the given passage EXCEPT

The four sentences (labelled 1, 2, 3 and 4) below, when properly sequenced, would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and choose the correct option.

1. The changes in the Earth's orbital tilt and precession (or the wobbling motion) occur because of gravitational forces emanating from other bodies in the solar system.

2. To understand exactly what happens, picture a spinning top when it is slightly disturbed.

3.  Just like a top, the Earth too wobbles slightly about its rotational axis.

4. This tilt changes between roughly 22 and 25 degrees about every 41,000 years, while the precession varies on about a 26,000-year period.

Most North Americans think minimal about American Indian culture and history. Researchers have concentrated such issues, yet they have not succeeded in broadcasting their decisions generally. Subsequently, it is as yet not generally realized that American Indians have epics, that they performed plays sometime before Europeans showed up, and that they practised politics and carried on the exchange system.

One way to gain a fuller appreciation of this rich culture is to examine American Indian poetry, for poetry is in all cultures the most central and articulate of the arts. It is especially important that we study American Indian poetry as this poetry can create a context that gives cohesive expression to the crafts, the artifacts, and the isolated facts that many Americans have managed to notice willy-nilly. Even a survey of American Indian poetry reveals a range of poetic thought and technique that defies easy generalization. Jarold Ramsey hazards a summary, however, which serves at least to give the uninitiated reader some sense of what American Indian poetry is like. Overall, he writes, it represents “an oral, formulaic, traditional, and anonymous art form,” whose approach is to emphasize the “mythic and sacred” components of reality. It “flourished through public performances. by skilled recitalists whose audiences already knew the individual stories” and valued the performers for their “ability to exploit their material dramatically and to combine them? their stories? in longer cycles” rather than for their “plot invention.” Because this poetry belongs to highly ethnocentric tribal peoples, whose cultures “we still do not know much about,” it “is likely to seem all the terser, even cryptic.”

American Indian poetry has another feature that Ramsey ignores: it is always functional. Whether sung, chanted, or recited; whether performed ceremonially, as entertainment, or as part of a task such as curing a patient or grinding corn; or whether recited individually or by a group, it is always fully woven into the fabric of ordinary life.

For complicated reasons, American Indian poetry has basically been ignored by non-Indian cultures. Kenneth Lincoln writes that failure to hear American Indian voices results “partly.from the tragedies of tribal dislocation, partly from mistranslation, partly from misconceptions about literature, partly from cultural indifference.” Brian Swann suggests an additional explanation: tribal poetry is oral, whereas Europeans arrived in the New World with a deeply ingrained belief in the primacy of the written word. As a result, European settles found it hard to imagine that poetry could exist without written texts and thus that the American Indians had achieved something parallel to what Europeans called literature long before Europeans arrived. As a consequence, Europeans did not fully respond to the rich vitality of American Indian poetry.

What would be unconventional for American Indian Poetry, as per the given passage?