Hi! :)
Answer: Dr. Garcia should compare fly cells to human cells.
Well sickle cell disease requires two homozygous recessive alleles so you would have the disease but if your'e heterozygous you have the sickle cell trait.
Differentiated cell and tissues can not make a new cell.
So, this includes parenchyma, phloem, <span>xylem.
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Yes rocks and mountains can't contain DNA