Eukaryotic cells all feature a nucleus, and their organelles are enclosed inside <span>membranes</span>
Answer:
b) spontaneous reverse mutation
Explanation:
Spontaneous mutations are produced by natural biological processes, while induced mutations are produced by mutagenic agents that trigger nucleotide errors in the DNA sequence. In the first phase of the experiment, Sally generated an induced mutation by using 5-bromouracil. The resulting strain required a constant supply of tryptophan to grow.
A reverse mutation restores the wild-type phenotype modified by a forward mutation, thereby reversing the phenotypic alteration to its original state. In a second step of the experiment, the colonies grew without the supply of tryptophan, thereby evidencing that the mutation was reversed in the original colony.
I think the correct answer from the choices listed above is the third option. It would be forming a hypothesis the step <span>in a scientific investigation that a scientist usually do before performing an experiment. It is very important in making research studies.</span>
Http://www.indiana.edu/~geol105/images/gaia_chapter_3/wegener.htm
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