the appearance and disappearance of group of organisms
b makes sense to me
Hey! Your answer would be the appearance and disappearance of group of organisms . Hope this helps!
The geological time scale refers to the sequential arrangement of all the major and minor events that have taken place in the past. This scale is divided into some major eons and eras and some subdivisions such as period and age.
The eras and periods are primarily marked by the appearance and disappearance of a group of organisms that allowed the geological time to be separated. There are three main eras namely the Paleozoic, the Mesozoic, and the Cenozoic.
The Paleozoic era was marked by the presence of simple organisms and index fossils both in the terrestrial as well as in the marine ecosystem, such as trilobites, fishes, reptiles, brachiopods, bivalves, and gastropods.
The Mesozoic era was marked by the presence of dinosaurs that ruled the earth's surface some 150 million years back. They were dominantly present and scattered in almost all parts of the land.
The Cenozoic era is the third one that is marked by the appearance, evolution, and presence of various groups of organisms such as horses, mammals, and humans.
Thus, the correct answer is option (2).
the appearance and disappearance of groups of organisms
(d) by finding the absolute age of the rockExplanation:
The relative age of a rock is not an exact number or age; rather it's the comparison of one rock or fossil to another to determine which one is older or younger. Scientists use carbon dating to calculate the age of a rock. Organic material from the rock is tested and that information is used to calculate the estimated age.
Answer to Q2:
C) Rock layersExplanation:
The Fossil Record and Geologic Time Fossils of plants and animals are present in some rocks. These fossils contribute to our understanding of geologic time and they show us the time span when and how a civilization used to live.Answer to Q3:
(c) They get a sense of the history of the area they are investigating.Explanation:
Fossils scaled into rocks are fundamental to the geologic time scale. For instance rocks formed during the Proterozoic Eon may have fossils of relative simple organisms, such as bacteria, algae, and wormlike animals while Rocks formed during the Phanerozoic Eon may have fossils of complex animals and plants such as dinosaurs, mammals, and trees.Answer to Q4:
(a)the appearance and disappearance of groups of organismsExplanation:
the appearance and disappearance of groups of organisms in different geological eras of earth history shows the time span of that era. This time span can be easily determined from the fossils present on sedimentary rocks because they show the family or group of those species which were present in that particular time period.Answer to Q5:
Scientists use radioactivity techniques to determine the age of earth. As we know radioactive substances emit energy continuously and they have a certain half life period so calculating the half life period can show us the age of earth by comparing the half lives of different radioactive elements. For example in uranium-lead dating, for instance, the radioactive decay of uranium into lead proceeds at a reliable rate.Answer to Q6:
Mostly sedimentary rocks like limestone and shale are the best options in the formation of fossils. Igneous rocks are formed directly from hot lava that is why they would not be able to preserve any remnants of living organisms that fall in it during its formation.Answer to Q7:
The granite is older than the sandstone.Explanation:
The principle of inclusions states that with sedimentary rocks, if inclusions are found in a formation, then the inclusions must be older than the formation that contains them. So in simple words pieces of the older rock will be included in the younger rock therefore option B is the correct answer.
the answer is translated आशा है कि मैंने मदद की.
the creation of n...