Nucleotides is

Options

A. A phosphoric acid group
B. A nitrogenous base
C. A pentose sugar
D. All of these

Answer

**Step-by-Step Solution:**

1. **Definition of Nucleotide:**
A nucleotide is the basic building block of nucleic acids, which are essential biomolecules in living organisms.

2. **Components of Nucleotide:**
A nucleotide is composed of three main components:
- **Pentose Sugar:** This is a five-carbon sugar molecule. In nucleotides, the sugar can either be ribose (in RNA) or deoxyribose (in DNA).
- **Nitrogenous Base:** This can be one of several types of bases. In DNA, the bases are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, the bases are adenine (A), guanine (G), cytosine (C), and uracil (U).
- **Phosphate Group:** This is a group consisting of phosphorus and oxygen, which is attached to the sugar molecule.

3. **Structure of Nucleotide:**
The general structure of a nucleotide can be represented as follows:
- The pentose sugar is at the center.
- The nitrogenous base is attached to one side of the sugar.
- The phosphate group is attached to the other side of the sugar.

4. **Types of Nucleotides:**
- Nucleotides can vary based on the type of nitrogenous base they contain. For example:
- In DNA: Adenine, Guanine, Cytosine, Thymine.
- In RNA: Adenine, Guanine, Cytosine, Uracil.

5. **Conclusion:**
Therefore, a nucleotide consists of a pentose sugar, a nitrogenous base, and a phosphate group. The answer to the question "Nucleotides is" is that nucleotides are composed of all of these components.

**Final Answer:**
Nucleotides are composed of a pentose sugar, a nitrogenous base, and a phosphate group. Thus, the correct answer is "all of these."

---