Complete the diagram below. Write NO MORE THAN TWO WORDS for each answer.

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问题     Complete the diagram below.
    Write NO MORE THAN TWO WORDS for each answer.
  
OPAL: Okay, at this point I think we should look at mangroves...they’re important for nutrient removal...
PERRY: I thin k ’nutrient recycling’ is more accurate...and biological productivity...because wetlands are really very productive ecosystems.
OPAL: Should we do a food web, then?
PERRY: We should do a diagram of some sort showing the importance of mangrove trees but maybe not a food chain...
OPAL: How about you explain it while I try and sketch it?
PERRY: Right. Well, let’s start with the mangrove trees. They’re very special because of their aerial roots that allow them to breathe even when the tide is high and their roots are under water. They can live in salt water and the salt enters through the roots, travels up to the older leaves and then these die and drop back into the water. A unique feature of mangroves is their ability to develop leaves on their seeds while they’re still on the tree and the seedlings drop down planting themselves directly into the mud underneath.
OPAL: Mum, got that. What happens to those older leaves that fall?
PERRY: The fallen leaves, or litter, decay in the water and form a rich mud that feeds bacteria, worms and small crustaceans.
OPAL: You mean things like prawns and crabs feed on the decomposed leaves?
PERRY: Yes, and even little fish do as well.
OPAL: And bigger fish feed on them.
PERRY: Eventually the remaining organic matter—which is now just very tiny particles--is taken up through the root system providing nourishment for the mangrove trees.
OPAL: And the cycle begins all over again.
PERRY: Yes, that’s exactly it, that’s what we’ll call it—the nutrient cycle of mangrove litter.
OPAL: Great. I’ll go home and work on this and we’ll meet again tomorrow.
PERRY: Okay, see you then.

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答案seedlings

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