The life cycle of certain ferns involves an alternation of generations between a haploid gametophyte and a diploid sporophyte.
In a particular species of fern, the haploid gametophyte contains 30 chromosomes in each cell.
Given that a single double-stranded DNA molecule consists of two complementary polynucleotide strands, calculate the total number of individual strands of DNA present in the nucleus of a zygote cell immediately before mitosis begins (after DNA replication has occurred).
