In Genesis 6, God tells Noah to bring two of every kind of animal into the Ark.
Genesis 6:19–20 instructs Noah to bring a male and a female of every kind of bird, land animal, and ground-moving creature. The pair is intended to preserve life and allow the animals to reproduce after the Flood.
A related passage creates a common point of confusion. Genesis 7:2–3 tells Noah to take seven pairs of clean animals and birds, while unclean animals are taken as one pair. Readers therefore encounter both the general pair-of-each-kind instruction and the later, more specific distinction for clean and unclean animals.
The answer “two” fits the wording of Genesis 6. It does not mean that every category in the full narrative is always represented by only one pair, because the later instructions assign different numbers to clean animals and birds.