Answer:
(C RNA can catalyze biological reactions and most likely appeared before DNA.
Explanation:
From my knowledge, I believe...
RNA most likely appeared before DNA and is known to be an unstable molecule.
<em>kiniwih426</em>
Answer:
After 6000 years, approximately 500 atoms of carbon-14 will be left in the femur bone of an animal which had 1000 atoms of carbon-14 when the animal died.
Explanation:
The half-life of a radioactive isotope of an element is the time taken for half the atoms present in a given amount of the element to undergo decay or disintegration. For example, the half-life of carbon-14 isotope is 5730 years. This means that, if there are 100 atoms of carbon-14 present in a given sample of a material, in the next 5730 years, approximately, 50 atoms of carbon-14 will be left in the material.
Since the half-life of radioactive isotopes are constant, these radioactive isotopes are used in the determining the ages of ancient life-forms as well as rocks.
In the given example, after 6000 years, approximately 500 atoms of carbon-14 will be left in the femur bone of an animal which had 1000 atoms of carbon-14 when the animal died.
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The rocky upper layer of the solid earth is called the "lithosphere". This rocky part includes the brittle upper portion of the mantle and also of the crust. It is bounded by the atmosphere above and of the asthenosphere which is another part of the upper portion of the mantle.
