A laboratory freezer can operate at which of the following temperatures?

• A. -20 C
• B. -70 C
• C. 4 C
• D. -20 or -70 C

Answer: (D)

Lab freezers come in different types to meet different storage needs. A standard laboratory freezer usually runs at -20 C, which is sufficient for many common specimens. Ultra-low temperature freezers reach around -70 C, which is essential for long-term preservation of sensitive materials like RNA, DNA, and certain proteins. The temperature 4 C is the typical refrigerator range and is not a freezer. Because labs can have freezers at either -20 C or -70 C depending on what they’re storing, the correct understanding is that a laboratory freezer can operate at either temperature.