Answer:
Changes in gene expression
Explanation:
This phenomenon is the result of changes in gene expression. That means, how the information in the DNA is used by the cell. The genes that are active in the cells of the brain will be very different from the genes that are active in the cells of the bone marrow.
These patterns of gene expression are different for each cell, and dictate the identity of that cell. Gene expression patterns are controlled by a variety of factors in the cell that allow tissue-specific expression, such a transcription factors.
This can also be facilitated by another layer of regulation called epigenetics, which literally means "on top of" genetics, and refers to modifications of DNA (and the proteins around it), that can reflect and influence the activity of the genes within.
Answer:B.
It was used to prove that smoking causes health problems.
Explanation:
Answer:
D.
Explanation:
Natural selection is the way that organisms adapt through adaptations to better survive and pass on the special genes which enable the offspring to survive. Saying an organism will always mutate to survive is wrong, as natural selection implies that not all organisms survive. With natural selection, nothing is "selected", so B and C are not correct. However, mutations DO make organisms "more fit" to survive their environments, so D is the answer.
