i think four phenotypes can be produced
Answer:
E) Has neither surface antigen A nor B on its erythrocytes
Explanation:
Blood contains the blood fluid called plasma and blood cells of different types. The cells of the blood also contain antigens on their surface which could activate immune system to eradicate the pathogens.
On the basis of the presence of these antigens, the red blood cells are categorized into four types that is A,B, AB and O.
The person with blood group A will have A antigens on the red blood cells, B blood group will have B antigens on the blood group and with O blood group will not have neither A nor B antigen on its surface.
Thus, Option-E is the correct answer.
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Answer:
D. They define geological periods because scientists use them as reference points for tracking the history of the earth.
Explanation:
Catastrophic events related to changes in geological timeline are very useful in defining geological periods.
These events have very significant appearance in the geological record and can be used to determine the history of the earth.
The catastrophic events usually culminates into extinction cycles or termination of some organisms from the earth surface.
Geologists use these events that are often wide spread to delineate geological periods.