Deoxyribonucleoside triphosphate acts as ________ and they provide________ for polymerisation.

Answer

### Step-by-Step Solution:

1. **Understanding the Components**:
- Deoxyribonucleoside triphosphate (dNTP) is a molecule that consists of a deoxyribose sugar, a nitrogenous base, and three phosphate groups.

2. **Role of dNTP in Polymerization**:
- In the context of DNA synthesis, dNTPs serve as the building blocks (monomers) that are linked together to form a DNA polymer.

3. **Function as a Substrate**:
- dNTPs act as substrates in the polymerization process. A substrate is a substance on which an enzyme acts. In this case, the enzyme DNA polymerase uses dNTPs to synthesize DNA.

4. **Energy Provision**:
- The high-energy bonds between the phosphate groups in dNTPs provide the necessary energy for the polymerization reaction. When a dNTP is added to a growing DNA strand, two phosphate groups are released, and this release of energy drives the formation of the phosphodiester bond between nucleotides.

5. **Final Answer**:
- Therefore, the complete answer to the question is: "Deoxyribonucleoside triphosphate acts as **substrate** and they provide **energy** for polymerization."