Cambridge IELTS 21 · Academic · Test 4 · Passage 1
Water Hyacinth in Kenya — IELTS Reading Answers
All 13 answers for Water Hyacinth in Kenya, Cambridge IELTS 21 Academic Reading Test 4 Passage 1, with evidence and explanations.
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Water Hyacinth in Kenya answer key at a glance
Questions 1–13. Tap an answer to see the evidence.
What this passage tests
The passage traces how an ornamental South American plant became an invasive problem on Lake Victoria, then a possible fuel source. Questions 1-7 are True/False/Not Given, 8-10 complete a flow chart and 11-13 complete notes on the benefits and the barrier to adoption.
Questions 1–7: True / False / Not Given
Strategy: Judge the whole statement against the text. FALSE contradicts the passage; NOT GIVEN means the passage never addresses that specific claim.
Water hyacinth was introduced as a decorative plant in east Africa.
“In east Africa the plant arrived with Belgian colonists in Rwanda, who liked the look of its glossy leaves and delicate purple flowers floating in their ponds”
TRUE: Belgian colonists in Rwanda 'liked the look of its glossy leaves and delicate purple flowers'.
Fishermen took some water hyacinth plants to Lake Victoria.
“it had 'escaped' out of the country via the Kagera river and made its way downstream to Lake Victoria”
FALSE: the plant 'escaped' down the Kagera river; fishermen did not carry it to Lake Victoria.
It is now difficult to force boats through the thick water hyacinth on Lake Victoria.
“as the boats that once brought the fish to shore by the hundreds struggle to navigate through the mass of plants”
TRUE: boats 'struggle to navigate through the mass of plants'.
Chemicals produced by the water hyacinth plants are affecting the numbers of fish in Lake Victoria.
“There, with no natural predators and perfect temperature conditions, the plant began spreading in the open water, blocking fishing routes and providing a new habitat for disease-carrying mosquitoes”
NOT GIVEN: chemicals produced by the plant and their effect on fish numbers are never discussed.
Cooking with charcoal has been proved to be even worse for people's health than cooking with wood.
“About three out of four families in Kenya depend on wood or charcoal to cook their daily meals, and the rate is even higher in rural areas, Kenya’s latest demographic and health survey shows. Using solid fuels like these for cooking increases indoor pollution”
NOT GIVEN: the passage compares wood and charcoal use but never proves charcoal is worse for health.
People found it impossible to remove much water hyacinth from Lake Victoria.
“Some years ago, on the shores of Lake Victoria, huge piles of water hyacinth that villagers had taken out of the water in an attempt to clear it were a common sight”
FALSE: villagers took 'huge piles' of water hyacinth out of the water, so removal was possible.
Scientists started investigating the possibility of using water hyacinth to generate biogas in the last century.
“It's a magic combination that has captivated researchers' imaginations since as early as the 1980s when, across the world, they began to explore its potential as a biofuel”
TRUE: researchers began exploring biogas potential 'as early as the 1980s'.
Questions 8–10: Flow Chart Completion
Strategy: Follow the arrows in order. Each stage usually maps to one sentence or one clause in the passage.
“The community received a pair of donated biogas digesters - machines that would transform a mix of water hyacinth and cow dung into biogas for cooking”
The digesters transform 'a mix of water hyacinth and cow dung into biogas'.
“The mixture goes in one end - think of it as a mouth - and over the next 20 to 30 days, it goes through a fermentation process and breaks down, giving off gas that comes out the other end”
Over 20 to 30 days the mixture 'goes through a fermentation process'.
“From there, the clean-burning gas is passed through pipes to the point of use, just like traditional domestic gas”
The gas is 'passed through pipes to the point of use'.
Questions 11–13: Note Completion
Strategy: Predict the word class from the note, find the paraphrase of the note's keyword in the passage, then copy the answer exactly within the word limit.
“Besides, they don't have to devote a lot of time every day to gathering firewood, which is a great relief”
Families no longer 'devote a lot of time every day to gathering firewood'.
“As a result, they're able to make more money for their families from other enterprises”
They can 'make more money for their families from other enterprises'.
“But unless the price of the machines drops, it's pretty clear that most communities will never be able to afford any, since they sell for about $750”
'Unless the price of the machines drops', most communities cannot afford one.
Learn the question types in this passage
Traps in this passage
- Question 2 is FALSE because the plant 'escaped' down the Kagera river; fishermen did not carry it.
- Question 5 is NOT GIVEN: the passage compares wood and charcoal use but never ranks their health effects.
- The flow chart follows a physical process. Keep the stages in order: cow dung, fermentation, pipes.
Frequently asked questions
Where does the Water Hyacinth in Kenya passage come from?
It is Passage 1 of Cambridge IELTS 21 Academic Reading Test 4, and it covers Questions 1–13.
What question types appear in Water Hyacinth in Kenya?
The passage is tested with True / False / Not Given, Flow Chart Completion, 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.