All questions of The Origin of Life for Grade 9 Exam

Bcoz epiglottis helps in obstructing the entry of bolous into the trachea

The earliest undisputed evidence of life on Earth dates at least from 3.5billion years ago, during the Eoarchean Era, after a geological crust started to solidify following the earlier molten Hadean Eon.

Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years.

Vestigial organs means evidence for the evolution.. so as per the given option...wisdom teeth is the vestigial organ...so the option B is correct...

Mammals appeared on the earth long before the extinction of the dinosaurs; in fact, dinosaurs and mammals originated within 10 million years of each other, in the late Triassic about 200 million years ago.........

Organs such as bats of wings, wings of birds, seals of flippers, arms of humans have common underlying anatomy. That was present in last common Ancestors. forelimbs are homologous organs. homology refers to the traits inherited by two different organisms from common ancestry. so it has similar origin and different or similar functions.
So option " A " is correct answer.

During Azoic  era, the earth was with out plants and animals. The rock layers which were formed soon after azoic era contains the remains of limy sea plants.The word "Azoic" is derived from the Greek, a- meaning without and zoon meaning animal (or living being), it was first used to mean without life.....

The Cenozoic era is the most recent of the three major sub division of the animal history. The other two are the Mesozoic and Peliozoic eras. The Cenozoic era only about 65 million years. From the end of the Cretaceous period and the extension of non avian dinosaurs to the present. The Cenozoic is sometimes called as age of mammals because the largest land animals have been mammals during that time.
So option " C " is correct answer.

If a starfish possess 6 arms instead of 5 it's an example of variations. Because it is in difference between cells individual organisms of any species caused either genetic difference. Variations may show physical appearance, metabolism, fertility.., etc..,
So option " A " is correct answer.

Mesozoic era or middle life era is the life diversified rapidly and giant reptiles,dinosaurs and other monstrous beads roamed the earth. so it is called as age of reptiles era.

C

The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (ontogeny), goes through ...

D

Origin is different and function same

Fossils are dated using various methods, and one such method is the use of radioactive carbon compounds. This method, known as radiocarbon dating or carbon-14 dating, allows scientists to determine the age of organic remains by measuring the amount of radioactive carbon-14 present in the sample.

Radiocarbon dating is based on the fact that carbon-14 is a radioactive isotope of carbon that is constantly formed in the atmosphere by cosmic rays. This carbon-14 is then absorbed by living organisms, such as plants and animals, through the process of photosynthesis or consumption. When these organisms die, the carbon-14 in their bodies begins to decay at a predictable rate.

The decay of carbon-14 is measured by its half-life, which is the time it takes for half of the carbon-14 atoms to decay into nitrogen-14. The half-life of carbon-14 is approximately 5730 years. By measuring the ratio of carbon-14 to carbon-12 in a fossil, scientists can determine how long it has been since the organism died.

To determine the age of a fossil using radiocarbon dating, scientists extract a small sample of organic material, such as bone or wood, from the fossil. They then measure the amount of carbon-14 in the sample using a technique called accelerator mass spectrometry. This method allows for incredibly precise measurements of carbon-14 levels, even for samples that are thousands of years old.

By comparing the amount of carbon-14 in the sample to the known levels of carbon-14 in the atmosphere at the time the organism died, scientists can calculate the age of the fossil. This method is particularly useful for dating fossils that are less than 50,000 years old.

In conclusion, fossils are dated using radiocarbon dating, which involves measuring the amount of radioactive carbon-14 in the sample. This method allows scientists to determine the age of organic remains by comparing the carbon-14 levels to known atmospheric levels. Radiocarbon dating is a valuable tool in paleontology and archaeology, providing insights into the age and history of ancient organisms.

Prototherians appears to be a combination of reptiles,birds and true mammals. The ancestors of this group are Eutherians and Metatherian. Prototherians split from their ancestors before these become the placental mammals and hence, formed a separate group. They adapted to harsher and diverse groups.

The evolutionary term descent with modification is most often associated with human evolution, but it is actually a more general term than that would suggest. Simply put, descent with modification means that traits are passed down from generation to generation and sometimes undergo changes or modifications over time. These changes may be caused by natural selection or even a mutation of DNA. It is a theory of organic evolution.

B option-- RECENT

man originated in coenozoic era, which is presently the lastest era, among these, Recent is the correct answer

The Mesozoic Era is literally the era of middle life. It is also known as the age of dinosaurs. It lasted from 245 to 65 million years ago and is divided into the three periods. The Mesozoic began with the supercontinent Pangaea. Then, during the era, Pangaea broke up and the continents drifted apart. The movement of continents changed climates. It also caused tremendous volcanic activity. Mass extinctions occurred at the end of the Triassic and Cretaceous Periods. The first extinction paved the way for a dinosaur takeover. In the second extinction, the dinosaurs finally disappeared

Fossilization occurs after an organism dies and only affects hard body parts, such as bones and shells. Soft flesh, scales, and feathers will not become fossils, although, imprints of these parts are sometimes made. In order for fossilization n to occur three things must happen. First, an organism dies.