Cambridge IELTS 21 · Listening · Test 3 · Part 4
Invasive Species — IELTS Listening Answers
All 10 answers for Invasive Species, Cambridge IELTS 21 Listening Test 3 Part 4, with the transcript evidence and an explanation for each.
← All Cambridge 21 Listening Test 3 answers
Invasive Species answer key at a glance
Questions 31–40. Tap an answer to see the evidence.
What this part tests
This part is tested with Note Completion (Q31–40). Each section below gives the strategy for that question type, the answers, and the sentence that proves them.
Questions 31–40: Note Completion
Strategy: Predict the word class from the note, find the paraphrase of the note's keyword in the transcript, then copy the answer exactly within the word limit.
“First of all, invasive species may eat native species, or sometimes they may bring a disease with them, which native species have never faced before and therefore have no defences against”
One impact: invasive species 'may bring a disease with them' that native species have no defences against.
“Species invasions are one of the biggest causes of damage in an ecosystem, actually putting its survival at risk”
Scale of harm: invasions cause 'damage in an ecosystem, actually putting its survival at risk', so 'ecosystem'.
“This could be intentional, or it could be accidental, such as when people who've been on holiday in another country come back with, say, the seeds of plants on their clothes or shoes”
Accidental route: people 'who've been on holiday in another country come back' with seeds on clothes or shoes.
“But sometimes humans deliberately move animals and plants around the world, for example to use them to control pests on farms, or to be pets”
Deliberate reason: species are moved 'to use them to control pests on farms, or to be pets', so 'pets'.
“It was hoped that the toads would eat the grey-backed beetles responsible for destroying crops of sugar on many of the plantations”
The crop attacked was 'sugar on many of the plantations', so 'sugar' names what the beetles destroyed.
“Another invasive plant is rhododendrons, which can be found in UK parks and woodlands. Their introduction dates back to 1763, but they're now seen as harmful because they block out so much light that native wild flowers can't grow beneath them”
Harm explained: rhododendrons 'block out so much light that native wild flowers can't grow beneath them'.
“Grey squirrels have outcompeted the smaller, native red squirrels. They both eat the same food, and the grey squirrels carry a type of virus that is deadly to the red squirrels”
Grey squirrels 'carry a type of virus that is deadly to the red squirrels', so 'virus' is the answer.
“The first step in controlling invasive species is learning about the behaviour of new species coming into the country. Monitoring is an important part of this, so that we can know if the new species begins to have a negative impact in its new environment”
Step one: 'learning about the behaviour of new species coming into the country', followed by monitoring.
“One effective way to keep track of invasive species is to create a database for the whole country”
Tracking method: 'create a database for the whole country', so 'database' follows 'a'.
“They should be encouraged to photograph harmful species – because this helps with identification – and then to report when and where these were observed”
Public help: people 'should be encouraged to photograph harmful species', which aids identification, then report sightings.
Learn the question types in this part
Frequently asked questions
Where does the Invasive Species listening section come from?
It is Part 4 of Cambridge IELTS 21 Listening Test 3, and it covers Questions 31–40.
What question types appear in Invasive Species?
The part is tested with Note Completion. Each type is explained on this page, alongside the answers.
Are these reading answers reliable?
Every answer is paired with the sentence that proves it, so you can check each one against the passage yourself. Use the page after a timed attempt, not instead of one.
Cambridge IELTS is published by Cambridge University Press & Assessment. Band9Prep is not affiliated with Cambridge. This page is an independent study aid: it gives the answer key, the passage evidence and an explanation so you can review an attempt you have already made.