The Precambrian eon is separated from the Phanerozoic eon in the fossil record because of the sudden appearance of organisms.
Explanation:
Precambrian eon is the initial existence on earth that can be predicted by the study of rocks and remaining of fossils. It has been seen as the existence of skeleton in this era, before this era no such things has been observed, even the development of sexual reproduction.
The Phanerozoic era comes after the Precambrian era, more advanced kinds of fossils of animals had been observed in this era. Phanerozoic era period of life on earth. Large organisms sudden appearance are seen in the Phanerozoic era i.e. First dinosaurs, mammals, fishes, angiosperms,first vertebrates etc.
In a viral structure, the capsomere is made up of small protein subunit called capsid. The correct option is b.
<h3>What is capsid?</h3>
Viral capsids are nanometer-sized canisters with complex mechanical characteristics that encapsulate the viral genome inside one host, transit it, and then release it inside another host cell.
Capsids are small protein subunits that make up the b. All viruses contain DNA as their genetic material. Glycoproteins aid virus attachment to the host cell.
Thus, the correct option is b.
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