Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: Matter can be classified as transparent, translucent, or opaque depending on how it interacts with light. Answer: opaque
[A]: Depending on how matter interacts with light, it can be classified as transparent, translucent, or what?

[Q]: Passage: Sperm ( Figure below ), the male reproductive cells, are tiny. In fact, they are the smallest cells in the human body. What do you think a sperm cell looks like? Some people think that it looks like a tadpole. Do you agree?. Answer: sperm
[A]: What are the male reproductive cells called?

[Q]: Passage: Check Your Understanding Define nodes and antinodes. Solution Nodes are areas of wave interference where there is no motion. Antinodes are areas of wave interference where the motion is at its maximum point. Answer: motion
[A]:
Solution nodes and antinodes are both areas of wave interference, but they differ in the presence of what condition?