oof..... I really want to help but i don't know the answer
Answer: the answer is C hope it helps
Explanation:
Worship center! this is easy
A star passes through stages of instability and stability. When core hydrogen fusion begins in a pre main sequence star, the star enters a stage of <u>stability</u>.
When the body has sufficient mass, the collapsing gas and dust burn hotter which eventually reaches temperatures enough to fuse hydrogen into helium. Thus, the star turns on and becomes a main sequence star, powered by hydrogen fusion.
A pre main sequence star is a star in the stage when it has not yet reached the main sequence. Earlier it is a protostar that grows by acquiring mass from its surrounding dust and gas.
Hence, in the pre main sequence star stage, core hydrogen fusion begins and the star enters a stage of stability.
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People often conduct different kinds of studies. This study would best be described as systematic observational studies.
<h3>What is a systematic observational study?</h3>
Systematic observation studies is known to be a type of studies where the specification of the time of actions, attributes, or other variables are known to be documented or recorded and also the right steps to how they are to be recorded is also done.
Here, as compared to Lisa, The intent is to make sure that, under the same or quite similar scenario, all observers will have the same kind of results.
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