Final answer:
Interphase is the cell cycle phase during which DNA replication occurs, particularly in the S phase, and it is the longest phase of the cell cycle. This statement is true.
Step-by-step explanation:
The statement that interphase is the process during which DNA is duplicated/replicated and is the longest phase is indeed true. Interphase consists of several stages, primarily G₁ phase, S phase, and G₂ phase. The S phase is specifically responsible for DNA replication. During this phase, each chromosome's DNA molecule is synthesized to form two identical sister chromatids. This phase is crucial for the genetic continuity of the cells as it ensures each daughter cell receives an exact copy of the DNA during cell division.