**Answer:**

To calculate the number of moles of DNA present in 10^23 diploid cells of a human being, we need to consider the following factors:

1. **Number of chromosomes in a diploid cell:** A diploid cell in a human being contains 46 chromosomes, which means there are 23 pairs of chromosomes.

2. **Number of base pairs in a haploid human genome:** The human genome contains approximately 3.2 billion base pairs. Since a diploid cell has two copies of each chromosome, the total number of base pairs in a diploid cell is 2 * 3.2 billion = 6.4 billion base pairs.

3. **Number of base pairs in one mole of DNA:** One mole of DNA contains Avogadro's number (6.022 x 10^23) base pairs.

4. **Number of moles of DNA per diploid cell:** To calculate the number of moles of DNA per diploid cell, we divide the total number of base pairs in a diploid cell by the number of base pairs in one mole of DNA.

Number of moles of DNA per diploid cell = (6.4 billion base pairs) / (6.022 x 10^23 base pairs/mol)

Number of moles of DNA per diploid cell ≈ 1.06 x 10^(-14) mol

5. **Number of diploid cells in the human body:** According to the question, there are 10^23 diploid cells in a human being.

6. **Total number of moles of DNA in the human body:** To calculate the total number of moles of DNA in the human body, we multiply the number of moles of DNA per diploid cell by the number of diploid cells in the human body.

Total number of moles of DNA = (1.06 x 10^(-14) mol/diploid cell) * (10^23 diploid cells)

Total number of moles of DNA ≈ 1.06 x 10^9 mol

Therefore, the number of moles of DNA present in 10^23 diploid cells of a human being is between 7.3 and 7.8 (rounded to one decimal place).