1. Diamonds, an occasional component of rare igneous rocks called lamproites and kimberlites, have never been dated satisfactorily. However, some diamonds contain minute inclusions of silicate minerals, commonly olivine, pyroxene, and garnet. These minerals can be dated by radioactive decay techniques because of the very small quantities of radioactive trace elements they, in turn, contain. Usually, it is possible to conclude that the inclusions are older than their diamond hosts, but with little indication of the time interval involved. Sometimes, however, the crystal form of the silicate inclusions is observed to resemble more closely the internal structure of diamond than that of other silicate minerals. It is not known how rare this resemblance is, or whether it is most often seen in inclusions of silicates such as garnet, whose crystallography is generally somewhat similar to that of diamond; but when present, the resemblance is regarded as compelling evidence that the diamonds and inclusions are truly cogenetic.

Ques. The main purpose of the passage is to

2. In embarking on the fight for independence, America faced formidable obstacles. The Continental Congress did not have the authority to pass binding legislation or to impose taxes. The new nation had no army and no navy, and its population numbered only 2.5 million people, 20 percent of whom were slaves. Britain, by contrast, was a mighty power of 11 million people with the world’s best navy and a well-disciplined army. Fifty thousand troops were in North America in 1776, and Britain hired thirty thousand German soldiers to supplement its forces during the war. However, the American Revolutionaries were not deterred.

Ques  The main idea of the passage is:

3. At one time, one could only trace one’s family ancestry by writing letters, visiting courthouses, and begging relatives for any crumb of information. However, today with the World Wide Web, the task has become much simpler. Much of the archived history of our lives and our ancestors’ lives is readily available on-line. In addition, there are specific software programs in existence that will walk you through the process of creating a family tree and take you to appropriate Internet sites for record information. Another alternative is hiring someone or some company to do your tree for you. Depending on your dedication and time, a method is available for you. You might think about tracing your family roots. It is fun for many and will let you in on your family’s past. Even if you find a skeleton in the closet, maybe you could just ignore that twig of your family tree.

Ques. We may infer from the passage that

4. Follow the money and you will end up in space. That’s the message from a first-of-its-kind forum on mining beyond Earth. Convened in Sydney by the Australian Centre for Space Engineering Research, the event brought together mining companies, robotics experts, lunar scientists, and government agencies that are all working to make space mining a reality. The forum comes hot on the heels of the 2012 unveiling of two private asteroid-mining firms. Planetary Resources of Washington says it will launch its first prospecting telescopes in two years, while Deep Space Industries of Virginia hopes to be harvesting metals from asteroids by 2020. Another commercial venture that sprung up in 2012, Golden Spike of Colorado, will be offering trips to the moon, including to potential lunar miners.

The author of Passage mentions several companies primarily to

5. Since the Hawaiian Islands have never been connected to other land masses, the great variety of plants in Hawaii must be a result of the long-distance dispersal of seeds, a process that requires both a method of transport and an equivalence between the ecology of the source area and that of the recipient area.

There is some dispute about the method of transport involved. Some biologists argue that ocean and air currents are responsible for the transport of plant seeds to Hawaii. Yet the results of flotation experiments and the low temperatures of air currents cast doubt on these hypotheses. More probable is bird transport, either externally, by accidental attachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequent excretion of the seeds. While it is likely that fewer varieties of plant seeds have reached Hawaii externally than internally, more varieties are known to be adapted to external than to internal transport.

Ques. The author is primarily concerned with