During which phase can the defense cross-examine witnesses?

The correct answer is the presentation of evidence phase. In this phase, both the prosecution and the defense have the opportunity to present their cases, which includes examining witnesses. The defense can cross-examine witnesses during this time to challenge the testimony given by the prosecution's witnesses. This is a critical part of the trial process, as it allows the defense to seek inconsistencies in testimony, highlight any biases or motives of the witness, and provide an alternative perspective that may cast doubt on the prosecution's case.

In contrast, during the witness testimony phase, which is often encompassed within the presentation of evidence, the emphasis is on the actual testimony being delivered rather than the examination process itself. Opening statements occur before any evidence is presented and focus on outlining what each side intends to prove during the trial. Lastly, closing statements summarize the evidence and arguments made, but do not involve the examination of witnesses. Therefore, the presentation of evidence is the appropriate phase where the defense actively engages in cross-examining witnesses.