Phosphorus is present in `:`

Options

A. Protein
B. DNA and RNA
C. Amino acid
D. starch

Answer

To answer the question "Phosphorus is present in:", we will analyze each of the options provided:

1. **Protein**:
- Phosphorus is an essential element in certain proteins, particularly those that are involved in energy transfer and storage, such as phosphoproteins.

2. **DNA and RNA**:
- Phosphorus is a critical component of nucleotides, which are the building blocks of DNA and RNA. Each nucleotide contains a phosphate group, which is essential for the structure of these nucleic acids.

3. **Amino Acids**:
- While not all amino acids contain phosphorus, some amino acids, such as phosphoserine, do have phosphorus in their structure. However, phosphorus is not a standard component of all amino acids.

4. **Starch**:
- Starch is a polysaccharide made up of glucose units. Phosphorus is not a component of starch itself, but it can be involved in the metabolic processes that utilize starch.

After considering all the options, we can conclude that phosphorus is present in proteins, DNA, and RNA, and certain amino acids. However, it is not a direct component of starch.

**Final Answer**: Phosphorus is present in proteins, DNA, RNA, and certain amino acids, but not in starch.