The two strands of double helix of DNA are linked together by hydrogen bonds between :

Options

A. bases
B. deoxysugars
C. phosphates
D. ribose sugars

Explanation

To answer the question regarding how the two strands of the double helix of DNA are linked together, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding DNA Structure**: DNA is composed of two strands that form a double helix. Each strand is made up of a backbone consisting of sugar and phosphate molecules.

2. **Identifying Nitrogenous Bases**: The DNA strands contain four types of nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).

3. **Base Pairing**: The bases pair in a specific manner: adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). This pairing is crucial for the stability of the DNA structure.

4. **Hydrogen Bonds**: The pairs of bases are held together by hydrogen bonds. Adenine and thymine form two hydrogen bonds (a double bond), while cytosine and guanine form three hydrogen bonds (a triple bond).

5. **Conclusion**: Therefore, the two strands of the double helix of DNA are linked together by hydrogen bonds formed between the nitrogenous bases (A-T and C-G).

### Final Answer:
The two strands of the double helix of DNA are linked together by hydrogen bonds between the nitrogenous bases: adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G).

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