標本

1. Origins, structure, and basic meaning

• Structure: 標本 (ひょうほん) is a specimen preserved for observation or study. 標本を観察する uses a finished specimen; 標本にする marks a resulting state.
• Basic usage: Insect specimens are observed in a science room; a collected leaf is dried and made into a specimen.

2. Common pitfalls and similar expressions

• Preserved material observed and leaf prepared as a specimen
  • The first sentence takes a completed specimen as object; the second marks the leaf's resulting classification with に. Statistical sampling is outside these contexts.