Question

a zebra cell is just about to replicate its dna. what will happen first? the dna unravels to make two strands. the dna folds over itself to create a dense chromosome. rna attaches to dna. all of the cells dna attaches to proteins.

Explanation:

During DNA replication, the first step is the unwinding of the double - stranded DNA molecule. This unwinding is carried out by helicase enzymes, which break the hydrogen bonds between the complementary base pairs (A - T and G - C). Once unwound, each strand can serve as a template for the synthesis of a new complementary strand.

• The option "The DNA folds over itself to create a dense chromosome" is incorrect. Chromosome condensation occurs later in processes like mitosis, not as the first step of DNA replication.
• The option "RNA attaches to DNA" is part of processes like transcription (where RNA polymerase attaches to DNA to make RNA) or priming in DNA replication (where RNA primers attach to DNA). But it is not the first step of DNA replication.
• The option "All of the cell's DNA attaches to proteins" is a general statement about DNA - protein interactions (like histones in chromatin) but not the first step of DNA replication.

Answer:

The DNA unravels to make two strands.