The answer is D. Hope this helps!
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Fossil: is preserved pre historic life form present under ground at high pressure for a long time.Animal die and burried under layers of sediments.
It provides evidence about the history of life on earth. It also shows different groups of organisms, including species,that have changed over time. Because the formation of any fossil depends upon the precise combination of conditions.
As the world changes, plants and animals change with time . From fossils we compare organisms of modern time with ancient , the species we see today are very different from species that lived in the past. Thus, the fossil record can be used to show that organisms changed to meet new condition.
Tretinoin is a naturally occurring metabolite of retinol in the retinoid class, including natural and synthetic analogues. It is the acid form of vitamin AIt acts on cell growth and differentiation. Its main use is the treatment against acne thanks to its keratolytic and anti-inflammatory properties. Tretinoin is also used in the treatment of acute myeloid leukaemia type 3 (AML 3).
SIDE EFFECTS:
Among the expected effects, side effects may occur. Signs of an allergic reaction include: hives, difficulty breathing, swelling of the face, lips, tongue or throat;
It should be known that tretinoin can make you more sensitive to the sun, so use sunscreen every day, and wear protective clothing outdoors.
Cholesterol and triglycerides should be done before and during treatment because this drug could increase their values
Some patient with leukaemia treated by tretinoin has suffered from The syndrome of retinoic acid which is characterized by fever, dyspnea, acute respiratory distress...