Correct Answer: Option 3 – New York State was closer to equator

According to the map above, the present day corals are lined along the sea coasts in the equatorial belt. Hence, this shows that corals need the equatorial climate for survival and growth. And the reason for the fossils of the corals being present in some New York State bedrock is the possible presence of New York State in the equatorial belt in the past.

Correct Answer: Option 3 – Bothriolepis

Bothriolepis are the category of upper Devonian fish species which lived 380 million years ago.

The sedimentary rocks are a proof that life forms surviving in sea waters have lived in this region in the past and due to earth quakes and volcanoes, gradually the sea bed gave way for land mass and current day features.

Hence, option 3 is the correct answer.

Cloelophysis and Maclurites are the fossils of creatures surviving on land. Hence, options 2 and 4 are incorrect.

Correct Answer: Option 2 – B

A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time. Index fossils are the basis for defining boundaries in the geologic timescale and for the correlation of strata.

Index fossils help in dating other fossils found in the same sedimentary layer. For example, if you find a fossil from an unknown era near a fossil from a known time, you can assume that the two species were from about the same time.

They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil. If the species concerned were short-lived (in geological terms, lasting a few hundred thousand years), then it is certain that the sediments in question were deposited within that narrow time period. The shorter the lifespan of a species, the more precisely different sediments can be correlated, and so rapidly evolving types of fossils are particularly valuable. The best index fossils are common, easy-to-identify at species level, and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is low.

Correct Answer:

Correct Answer:

One half life of carbon-14 is 5730 +40 years. It takes 22,800 years for carbon – 14 to complete 4 half-lives.

Correct Answer:

Carbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 60,000 years.

One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites. When plants fix atmospheric carbon dioxide (CO2) into organic material during photosynthesis they incorporate a quantity of 14C that approximately matches the level of this isotope in the atmosphere. After plants die or they are consumed by other the 14C fraction of this organic material declines at a fixed exponential rate due to the radioactive decay of 14C. Comparing the remaining 14C fraction of a sample to that expected from atmospheric 14C allows the age of the sample to be estimated.

The tree trunk found in the upper layer of the section is a recent organic remain and can be dated using carbon-14 dating.

Garnet crystal, Trilobite, Graptolite and plagioclase crystal are inorganic substances and cannot be dated using carbon-14 dating.