<span>Activation energy refers to the amount of energy required by certain chemicals for them to have a reaction.
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Answer:
a deoxyribose (5-carbon sugar), a phosphate group, and a nitrogenous base (Figure 9.3). So the third option.
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.
Answer:
<em>Like every other organism the population size of the humans have increased over time.</em>
Explanation:
With the improvements in science and technology, life becomes better and better for human beings. In the past, when there were no discoveries for curing diseases, the human population declined because of the spread of various diseases and famine conditions.
But as the developments in the scientific world are made, it has been easier to cure diseases and other problems. As a result, the population size of the human goes on increasing.
Answer:
Human diploid cells have 23 pairs of chromosomes. Because of independent assortment during meiosis I, there are 223, or 8.4 million possible gametes that may be created even if crossing over didn't occur.