Cretaceous extinction also known as Paleogene extinction was a period of time when suddenly around three quarter of the animal and plant species began to get extinct from the land. The event happened around 66 million years ago and is considered as the end of cretaceous era that lead to the beginning of Mesozoic era.
Reasons for the mass extinction:
- Scientists think that a major asteroid or comet hit the surface of earth which deteriorated the earth’s environment, especially by making it difficult for plants to perform the process of photosysnthesis. This is called as Impact hypothesis and scientists think that it was the reason of extinction of so many species because they found debris of asteroid in the land.
- There could also be some other reasons like climate changes,volcanic eruptions and changes in the sea level which made the environment unfavorable for the survival of living organisms.
- One of the best known organism that is thought to extinct in cretaceous period was dinosaur.
Extinction of Dinosaurs:
As stated above the exact cause of dinosaur extinction can not be stated with confidence. This is because cretaceous period was the time when so many unfavorable circumstances took place like diseases, geologic events ,climate change etc.
However, the most believed theory is that some Asteroid hit the surface of earth and turned the climate very very old. Therefore, those amazing creatures were not able to survive that climate.
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Answer:
GIVe Them The DaM VaccIne sInce You already GOt It?
Explanation:
The correct answer to this question is this one: "sporozoans lack locomotor organs"
The feature that differentiates sporozoans from the other phyla of protozoans is that sporozoans lack locomotor organs. Sporozoans are a strictly parasitic protozoan that are usually immobile.
Answer;
C. it is the part f the atom with the greatest mass
Explanation;
The nucleus of an atom is a small dense region at the center of an atom that contains protons and neutrons.
Almost all the mass of an atom is located in the nucleus, with a very small contribution from the electron shells.
The protons are positively charged which gives the nucleus a positive charge while the neutrons have no charge.
Incomplete Dominance
Explanation:
Incomplete dominance is an example of a non-mendelian trait (doesn't follow the genetic rules established by Gregor Mendel). When two parents mate and produce offspring, the offspring is a blend of the two parents. So, a red flower and a white flower would make a pink flower.
