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.
Answer: the two tropics zones
Explanation:
Between the two tropics zones, which includes the equator, the Sun is directly overhead twice per year. Outside the tropic zones, whether to the south or north, the Sun is never directly overhead. Two other significant lines of latitude are the Arctic Circle (around the North Pole) and the Antarctic Circle (around the South Pole).