Francis Crick discovered the DNA structure.
Explanation:
<u>the Paleozoic Era </u>
The Precambrian era describes a period of time that pre-dates Cambrian. This time typically references the entire period of the history of earth before the formation of rocks containing identifiable fossils occurred. It covers the majority of Earth’s history and is divided into the Hadean, Archean and the Proterozoic era.
Just before the Cambrian eruption, in the Paleozoic Era the environment was oxygenated, culminating in an explosion of new life in the Proteozoic Eon (2500-541 million years ago) in the form of primitive blue-green algae named cyanobacteria and oxygen based species. Multicellular species followed later, along with structure at higher levels, and complex life. Oxygen levels grew gradually over this period of time, from low levels.
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The purpose of the replication bubble is that it forms where replication is taking place (option A).
<h3>What is replication?</h3>
Replication is the process of producing replicas or duplicate of DNA or RNA molecules.
DNA replication is a very important process that occurs prior to cell division. During replication, the double stranded DNA is separated into two single strands.
Each copy called the leading and lagging strand becomes the template for the synthesis of new DNA strands.
However, a structure called replication bubble is a formed during the separation of two DNA strands by the helicase enzymes.
Therefore, the purpose of the replication bubble is that it forms where replication is taking place.
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