Questions: When were cells first observed through a microscope? Mid-1500s Mid-1600s Mid-1700s Mid-1800s

The answer is the second one (Mid-1600s): the original text in the question...

Explanation for each option:

• Mid-1500s: Incorrect. The technology for microscopes was not sufficiently advanced during this period to observe cells.
• Mid-1600s: Correct. Cells were first observed by Robert Hooke in 1665 when he looked at a slice of cork through a microscope.
• Mid-1700s: Incorrect. By this time, cells had already been observed, and further advancements in microscopy were being made.
• Mid-1800s: Incorrect. This period is too late; cells had been observed much earlier.

Summary: Cells were first observed through a microscope in the mid-1600s by Robert Hooke.