1.Tyrannosaurus Rex Lived in the Mesozoic Era
2.The largest mass extinction happened in the Paleozoic Era
3.Life exploded for the first time in the Precambrian Era
4.The Chicxulub crater in the Cenozoic Era
Answer: The correct answer is- B) Ecosystem.
Ecosystem can be described as a group of living organisms present in a particular area that are interacting with each other as well as the non living components of that environment.
In other words, it is the interaction between biotic ( living such as plants and animals) and abiotic ( non living such as temperature, air, water) components of an environment.
Example- Pond ecosystem, lake ecosystem.
The correct statement is: (2) Sister chromatids are genetically identical.
Sister chromatids are the copies of a single chromosome. These are therefore genetically identical. The sister chromatids are joined together at the region called centromere with the help of certain proteins. The chromatids are formed during the S phase of the interphase due to a process called duplication.
Chromosome is the compact form of DNA. It consists of the genetic material and certain proteins called histone proteins. The main role of chromosome can be seen during cell division. This is because the division of genetic material takes place in the chromosomal form.
To know more about sister chromatids, here
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