Within the head of T4 phage _ molecule is present.

Explanation

Within the head of T4 phage, a double-stranded DNA molecule is present.Double-stranded DNA (dsDNA) is a molecule of DNA that consists of two complementary strands of nucleotides that are held together by hydrogen bonds. The two strands of dsDNA are arranged in an antiparallel fashion, meaning that the 5' end of one strand is paired with the 3' end of the other strand.The dsDNA in the head of T4 phage is about 150,000 base pairs long. It is tightly packed into a helix that is about 20 nanometers in diameter. The dsDNA is held in place by proteins called capsid proteins. The capsid proteins are arranged in a hexagonal lattice that forms a rigid structure that protects the dsDNA from the environment.