Answer:
The nitrogenous bases guanine and adenine are A. purines.
Explanation:
Adenine and guanine are purines, whereas the other two bases in DNA (thymine and cytosine) are pyrimidines. The main difference between purines and pyrimidines is the number of rings that the base has: purines have two rings while pyrimidines only have one ring.
In addition, phosphate group and sugar group cannot be the answer to this question because these two elements in addition to a nitrogenous base makes up a nucleotide.
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Answer: The troubling reality of humanity's over-sized and still expanding population and create highly effective programs to solve the problem. Our efforts focus on specific attitudinal drivers of ongoing rapid population growth.
Explanation: In fact, world population growth remains totally unsustainable over 230,000 people are added to world population each day. That is a net gain - births minus deaths. But few people understand the true drivers of this increasing world population. Even fewer know how to effectively intervene. Long established and widely practiced social norms low status of women & girls, bias against modern contraception, and large ideal family size are the strongest drivers rapid growth of the population. If somebody tries to tell you that population growth is "slowing down," ask them to explain the graphic on the left.
The metric system is based on 10.