A、They are not large enough to be seen. B、They are only freely floating plants. C、Jellyfish is a kind of plankton. D、All the pla

W: Hi, Tom.
M: Judy! I haven’t seen you in weeks. Where have you been?
W: In Florida.
M: What? Vacationing while the rest of us have been studying on campus in the February cold?
W: Not exactly. I spent most of my time underwater.
M: I don’t understand.
W: I was on a special field trip. I went with my marine biology class.
M: So you went scuba diving. What were you looking for, sunken treasure?
W: You might say so. The sea is full of treasures, all kinds of strange fascinating organisms. Our class concentrated on studying plankton.
M: I thought plankton are too small to be seen.
W: That’s a common misconception. As a matter of fact, the term Plankton covers a wide variety of freely floating plants and animals from microscopic one-celled organism to large ones such as the common jellyfish.
M: Jellyfish may be large enough to be seen, but they are transparent, aren’t they?
W: Yes, most plankton have transparent tissues as a way of protection. It makes them practically invisible to predators.
M: But not invisible to your biology class, I hope.
W: By concentrating, I was able to see the outlines of lots of different plankton. In fact, our professor even took photographs of Greeber Quadata, which are small oceanic snails.
M: That sounds like an interesting trip. But I think if I’d been in Florida in February, I’d much rather spend my time just swimming and lying in the sun.
W: I bet you would.
5. How did Judy spend most of her time in Florida?
6. What was Tom doing in February?
7. What do we learn about the plankton?
8. Why is it hard to see most plankton?