If a cell in G1 has 40 chromosomes, then in G2 there will be sister chromatids, and chromosomes after mitosis.

If a cell in G1 has 40 chromosomes, then in G2 there will be 80 sister chromatids, and 40 chromosomes after mitosis.

Explanation:

G1 is the first part of the cell cycle, in which the cell begins its new life. Different cells spend different amounts of time in G1, but when they reach the S phase they replicate their DNA to prepare for cell division. After phase S, comes phase G2, and then comes mitosis.

In this specific cell, there are 40 chromosomes in G1, and when the DNA replicates itself, there will still be 40 chromosomes, but these chromosomes will have two sister chromatids each, meaning that in phase G2 there will be 80 sister chromatids in total.

When the cell enters mitosis, the sister chromatids are separated and each one will go to one of the two cells that are generated because of this division. After mitosis, each daughter cell will have 40 chromosomes with only one chromatid each.