The question is incomplete. The complete question is attached below.
Answer:
1. DNA is the polymer of deoxyribonucleotides that contain the nitrogenous base, pentose sugar and phosphate group. The phosphate is attached with the 3 C position of the deoxyribose sugar. This leads to teh formation of phosphodiester bond.
2. The DNA backbone consists of phosphate and sugar. The nitrogenous bases are inserted inside the DNA molecule. These nitrogenous bases are linked together by the hydrogen bonds.
3. The adenine binds requires two hydrogen bonds to bind with thymine. This provide complementary nature to the DNA molecule. Uracil is present instead of thymine in RNA .
4. The guanine binds requires three hydrogen bonds to bind with cytosine. More amount of energy is required to break their bonds.
If two breaks occur in one chromosome, sometimes the region between the breaks rotates 180 degrees before rejoining with the two end fragments. Such an event creates a chromosomal mutation called an inversion.
My Answer: The death rate begins to fall, but birth rates remain high for a time. Why?: Many of our countries are in Stage 2, that is why the government is concerned about our overpopulation. Hope I helped! :D