During which phase(s) of all cycle the amount of DNA remain at 2C in 2n cell:-
(1)G₀ G₁
(2)G₂and M
(3)G₂ only
(4)G₁and S Please explain

During G0 and G1 phase the DNA amount remains 2C.
DNA replication occurs in S phase which is followed by G2 phase so, so both S and G2 will also contain 4C amount.
As the amount of DNA is with respect to the cell. M phase includes both karyokinesis and cytokinesis. And, as in karyokinesis there is no cell division it also has 4C amount of DNA with respect to the cell going under division.
Answer is 1)