Final answer:
In a diploid organism, somatic cells have twice the number of chromosomes as the haploid gametes. During the G2 phase of the cell cycle, the chromosome count is doubled due to DNA replication, so a somatic cell with a normal count of 24 will have 48 chromosomes in G2.
Step-by-step explanation:
If an organism's sex cells, also known as gametes, each contain 12 chromosomes, then we are discussing a diploid organism where the gametes are haploid. In such organisms, the somatic cells, or body cells, contain twice the number of chromosomes found in the gametes.
This is because somatic cells have a full set of chromosomes (one set from each parent), whereas gametes have only a single set intended for reproduction. During the G2 phase of the cell cycle, a somatic cell has already duplicated its DNA in preparation for cell division, thus doubling its chromosome count. Therefore, a somatic cell that normally has 24 chromosomes (2 x 12 from each sex cell) will have 48 chromosomes during the G2 phase as each of the 24 chromosomes would have been replicated. The correct answer to the question is then 48 chromosomes (Option 2).