Crossing over occurs at the four-strand stage when two homologous chromosomes, each consisting of a pair of sister chromatids, are paired. Each crossover involves just two of the four strands and generates two recombinant strands.
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I think the answer is C and D
True
Changes in the transcription of mRNA or the translation of a polypeptide are not considered to be mutations because they are not permanent changes to the cell.
Explanation:
The half-life of mRNA and proteins is short. mRNA has an average of 10 hours of life span while proteins have an average of several days. Therefore mutation in these biomolecules will only persist as long as this mutated mRNA of protein exists. After its life-span, the molecule is degraded and replaced by a non-mutated mRNA or proteins. This is because the piece of DNA that codes for the mRNA and subsequent protein is not mutated. A mutation on DNA is the permanent kind of mutations because DNA is a highly stable molecule that stores information about the cell.
Learn More:
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It’s the control group.
The reason why is because the experimental group is the group in which they are experimenting with while the control group isn’t receiving any experimentation
She was suffering from cervical cancer when cells were first taken from henrietta lacks. While she was being treated for cancer many years ago her cells were taken and have been cultured in the laboratory ever since. She was never communicated that her cells were being taken and neither she nor her family has stood recompensed.
