<h2><u>Answer:</u></h2>
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.
Adenine (A) binds with Thymine (T).
<span>Guanine (G) binds with Cytosine (C).
</span>
Adenine and Guanine are purines. Thymine and Cytosine are pyrimidines.
Hope this helps !
Photon
Scientists
can also glimpse the awful effects of Alzheimer's disease when they look at
brain tissue beneath the microscope:
Alzheimer's tissue has numerous fewer nerve
cells and synapses than a well brain.
<span>
<span>Plaques, unusual
clusters of protein particle, which are construct up between nerve cells.</span>
</span>
<span>
<span><span>Dead and dying nerve cells contain tangles,</span> which
are produce of twisted strands of a further protein.</span>
</span>
<span>Scientists
are not absolutely sure what causes cell death and tissue deficiency in the
Alzheimer's brain, but plaques and tangles are key suspects.</span>
