The Humungous Fungus - IELTS Reading Answers & Explanations
From Collins Practice Tests For IELTS 2 Academic Reading Test 2 · Part 1 · Questions 1–13
Reading Passage
You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.
The Humungous Fungus
If you were asked what is the largest organism in the world, what would your answer be? A blue whale or a redwood tree? Or perhaps a giant squid? You would be wrong. But this is understandable because the world's largest organism is largely hidden from sight and was discovered only relatively recently in 1998 in the soil of Oregon's Blue Mountains. It is a fungus nearly ten square kilometres in area and one metre deep. It may be not only the largest single organism in the world but also one of the oldest. Based on its current rate of growth, the fungus is thought to be around 2,400 years old; however, it is also possible that it has been growing for the past 8,650 years. Commonly known as the honey mushroom, the only visible evidence for the organism on the surface is groups of golden mushrooms that grow in forests during the autumn.
The discovery of the organism came about when Catherine Parks, a scientist at the Pacific Northwest Research Station in Oregon, heard about trees dying from root rot in a forest east of Prairie City. Using aerial photographs, she identified an area of dying trees stretching over a 5.6 kilometre area. She then collected samples from the roots of these trees. When she looked at the samples, Parks was able to confirm that many of the samples were infected by the same organism; the fungus had grown bigger than any other creature known to science. A combination of good genes and stable conditions has enabled it to spread. In addition, the dry climate of the region makes it difficult for new fungi to establish themselves and compete with established fungi.
The technique for identifying the fungus was developed in 1992, when the first gigantic fungus was discovered in Michigan. A PhD biology student, Myron Smith, discovered it in a hardwood forest, when he and his team were trying to find the boundaries of individual fungi. After a year of testing, they still had not found the boundary of a particular fungus. The next thing they did was develop new genetic tests to see if the DNA from the samples was from a single individual fungus and not closely related individuals. Eventually, they realised that they had found a 1,500-year-old fungus that weighed over 90 metric tonnes.
The honey mushroom fungus is the cause of a root disease that kills many trees in the US and Canada. It has fine filaments or tubes that grow along tree roots and connect together to form a mat. The mat then slowly consumes the food source: it produces chemicals that digest carbohydrates from the tree and interfere with the tree's ability to absorb water and nutrients, eventually leading to the death of the host organism. As well as producing feeding filaments, the honey fungus is able to spread by producing string-like growths that reach out to find new potential food sources. The fungus spreads very slowly over hundreds of years, seeking out food and killing its victims. Not surprisingly, forest service scientists are interested in learning to control the fungus but they also realise that it has an important role to play in the forest's ecology.
Fungi have both beneficial and harmful effects. They are essential because they decompose or break down waste matter on the forest floor and recycle nutrients. They are also central to many processes that are important to humans: they are vital to the process of making many kinds of food, including cheese, bread and wine. They have been used in the production of medicines, and particularly antibiotics. Even the golden mushrooms produced by the honey mushroom fungus are edible, though apparently not very tasty. On the other hand, fungi also form a major group of organisms harmful to plants and animals. Some mushrooms produced by fungi, such as the death cap mushroom and the fool's mushroom, are extremely poisonous to humans. Fungi can spoil food which has been stored, and of course they can kill trees and other plants.
Although to humans the idea of an enormous organism silently growing underground seems very strange, Tom Volk, a biology professor at the University of Wisconsin-La Crosse, explains that this may be in the nature of things for a fungus. 'We think that these things are not very rare,' he says. 'We think that they're in fact normal.'
Questions
Questions 1–7 True / False / Not Given
Do the following statements agree with the information given in Reading Passage 1?
Write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
Questions 8–13 Summary Completion
Complete the summary below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
The largest known organism is a fungus, the only 8 signs of which are mushrooms which appear in autumn. The fungus was discovered when a scientist was studying 9 across a large area of forest in Oregon. The fungus is responsible for a(n) 10 that kills the trees. Scientists determined that the fungus was a single organism by using 11 to see if DNA samples were from the same individual. Although the concept of an enormous organism living 12 is strange to humans, scientists think it may be 13.
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q1 | TRUE | It may be not only the largest single organism in the world but also one of the oldest. Based on its current rate of growth, the fungus is thought to be around 2,400 years old; however, it is also possible that it has been growing for the past 8,650 years | Excerpt/Passage Explanation: The passage explains that the fungus might be the oldest living thing. It says that while scientists think it is at least 2,400 years old, it could actually be as old as 8,650 years. Answer Explanation: The answer means that it is possible this fungus has lived longer than any other living creature on Earth. Reason For Correctness: The correct answer is TRUE because the passage mentions that the fungus "may be" one of the oldest organisms. The word "perhaps" in the question is a synonym for "may be" or "possible," which matches the uncertain but likely tone used in the text. The text provides potential ages of 2,400 or even 8,650 years to support this idea. |
| Q2 | NOT GIVEN | The discovery of the organism came about when Catherine Parks, a scientist at the Pacific Northwest Research Station in Oregon, heard about trees dying from root rot in a forest east of Prairie City | Excerpt/Passage Explanation: The passage confirms that Catherine Parks was a scientist working in Oregon, but it does not say anything about her choice or her feelings regarding where she worked. Answer Explanation: The answer is NOT GIVEN because the text does not mention if Catherine Parks had a desire or personal wish to work in Oregon; it only says that she worked there. Reason For Correctness: The correct answer is NOT GIVEN because while the passage tells us that Catherine Parks was a scientist at a research station in Oregon, it provides no information about her feelings, goals, or whether she specifically wanted to work in that state. We only know her location and her job, not her personal preferences. |
| Q3 | TRUE | Using aerial photographs, she identified an area of dying trees stretching over a 5.6 kilometre area | Excerpt/Passage Explanation: The passage explains that Catherine Parks looked at pictures taken from the air to find a very large space where trees were dying, which led her to discover the fungus. Answer Explanation: The answer is TRUE because the scientist, Catherine Parks, used pictures taken from the sky to find the place where the trees were dying and the fungus was growing. Reason For Correctness: The correct answer is TRUE because the text says that Catherine Parks used 'aerial photographs' to find an area of dying trees. In English, 'aerial' means something that is in the air or taken from the air, and 'photographs' are photos. By using these pictures from above, she was able to identify the specific location where the fungus was active before she went there to collect samples. |
| Q4 | FALSE | The next thing they did was develop new genetic tests to see if the DNA from the samples was from a single individual fungus and not closely related individuals | Excerpt/Passage Explanation: The passage explains that the scientists created new DNA tests to find out if the samples they found came from one giant living thing or from many separate fungi that were in the same family. Answer Explanation: The answer is FALSE because Myron Smith did not create a test to find out which other types of living things are related to fungi. He made a test to see if different pieces were actually part of one single fungus. Reason For Correctness: The correct answer is FALSE because the passage states that Myron Smith and his team developed genetic tests to determine if DNA samples belong to a 'single individual fungus' rather than 'closely related individuals' (different individual fungi of the same type). The question incorrectly states that the test was meant to identify 'which organisms are related to fungi,' which implies a broader goal of finding relatives of fungi in general, rather than distinguishing between specific individual organisms. |
| Q5 | TRUE | The mat then slowly consumes the food source: it produces chemicals that digest carbohydrates from the tree and interfere with the tree's ability to absorb water and nutrients, eventually leading to the death of the host organism | Excerpt/Passage Explanation: The passage explains that the fungus uses chemicals to break down and eat the tree's food (carbohydrates). This action harms the tree and causes it to die. Answer Explanation: The answer is True because the passage confirms that the fungus hurts trees by eating their carbohydrates. Reason For Correctness: The correct answer is True because the text describes how the fungus kills trees. It mentions that the fungus 'consumes' or eats the tree by using chemicals to 'digest carbohydrates'. This process damages the tree and causes it to die by blocking its ability to get water and nutrients. |
| Q6 | FALSE | Even the golden mushrooms produced by the honey mushroom fungus are edible, though apparently not very tasty | Excerpt/Passage Explanation: The passage says that people can eat the mushrooms from the honey mushroom fungus, although they might not like the flavor. Answer Explanation: The answer is false because the honey mushroom fungus actually produces mushrooms that people can eat. Reason For Correctness: The correct answer is false because the passage explicitly describes the golden mushrooms from the honey mushroom fungus as edible. In English, 'edible' means something is safe to eat and is the opposite of 'poisonous.' While the text mentions that other types of mushrooms like the death cap are poisonous, it confirms that the honey mushroom is safe for human consumption, even if it does not taste very good. |
| Q7 | NOT GIVEN | On the other hand, fungi also form a major group of organisms harmful to plants and animals. Some mushrooms produced by fungi, such as the death cap mushroom and the fool's mushroom, are extremely poisonous to humans | Excerpt/Passage Explanation: The passage states that fungi are an important group that can hurt plants and animals and that some mushrooms are dangerous to people, but it does not say that they are the biggest group of all harmful organisms. Answer Explanation: The answer means that the text does not tell us if fungi are the biggest group of living things that cause harm to people. Reason For Correctness: The correct answer is NOT GIVEN because the passage only mentions that fungi are a "major group" that can hurt plants and animals and that some types are very poisonous to humans. However, the text never says they are the "largest" group or compares them to other groups like bacteria or viruses. Since the text does not provide this specific ranking, we cannot say if the statement is true or false. |
| Q8 | visible | Commonly known as the honey mushroom, the only visible evidence for the organism on the surface is groups of golden mushrooms that grow in forests during the autumn | Excerpt/Passage Explanation: The passage states that the honey mushroom fungus is usually hidden, and the only proof that can be seen on the ground's surface are the groups of golden mushrooms that appear in the fall. Answer Explanation: The answer means something that can be seen with your eyes. Reason For Correctness: The correct answer is 'visible' because the passage explains that the giant fungus lives mostly underground and is hidden from sight. The only parts of this living thing that people can actually see are the golden mushrooms that grow above the ground during the autumn season. The text uses the word 'visible' to describe these mushrooms as the only proof on the surface that the fungus exists. |
| Q9 | trees dying / dying trees | Using aerial photographs, she identified an area of dying trees stretching over a 5.6 kilometre area | Excerpt/Passage Explanation: The passage says that Catherine Parks used pictures taken from the sky to find a big part of the woods where trees were losing their life. Answer Explanation: The answer refers to trees that were losing their life or were no longer alive. Reason For Correctness: The correct answer is 'trees dying' or 'dying trees' because the passage explains that a scientist named Catherine Parks first learned about the fungus because of 'trees dying from root rot'. She later used aerial photographs to look at an 'area of dying trees' that covered a large space. This study of the sick and dead trees is what led to the discovery of the giant fungus in Oregon. |
| Q10 | root disease | The honey mushroom fungus is the cause of a root disease that kills many trees in the US and Canada | Excerpt/Passage Explanation: The passage states that this specific fungus makes trees sick with a disease in their roots, and this sickness is what causes the trees to die. Answer Explanation: The answer is the name of a sickness that affects the roots of trees and makes them die. Reason For Correctness: The correct answer explains what the fungus does to the trees. In the fourth paragraph, the text states that the fungus is the 'cause' of a 'root disease.' It then says this disease 'kills many trees.' The summary describes the fungus as being 'responsible for' something that kills trees, which matches the description of the root disease in the text. |
| Q11 | genetic tests | The next thing they did was develop new genetic tests to see if the DNA from the samples was from a single individual fungus and not closely related individuals | Excerpt/Passage Explanation: The passage says that researchers created new scientific tests to look at the DNA and see if all the fungus parts were from one big individual. Answer Explanation: The answer 'genetic tests' means scientific checks of a living thing's DNA (the code that makes up a living thing) to see if different parts belong to the same individual. Reason For Correctness: The correct answer is 'genetic tests' because the passage explains that after failing to find the fungus boundaries for a year, the team used this specific method. They studied the DNA to prove that all their samples came from a single fungus and were not just many different fungi living close together. The summary specifically asks for the method used to check if the DNA samples were from the same individual, which matching keywords in the text confirm to be 'genetic tests'. |
| Q12 | underground | Although to humans the idea of an enormous organism silently growing underground seems very strange, Tom Volk, a biology professor at the University of Wisconsin-La Crosse, explains that this may be in the nature of things for a fungus | Excerpt/Passage Explanation: The passage explains that even though people might find it odd for a huge living thing to grow beneath the soil, it is actually quite normal for this type of life. Answer Explanation: The answer tells us the place where the big living thing grows. It grows below the dirt where people cannot see it. Reason For Correctness: The correct answer is found in the final paragraph of the text. It discusses how people find the idea of a giant creature growing 'underground' to be very odd or unusual. The word 'underground' fits perfectly into the summary to describe the location where the organism lives. |
| Q13 | normal | 'We think that these things are not very rare,' he says. 'We think that they're in fact normal.' | Excerpt/Passage Explanation: The passage shows a scientist saying that these large organisms are not hard to find. He believes that they are actually usual and expected. Answer Explanation: The answer 'normal' means that something is common or happens in a regular way, rather than being a rare or strange event. Reason For Correctness: The correct answer is 'normal' because the final paragraph of the text discusses the perspective of scientists. While most people find it strange that a living thing could grow so huge, a biology professor explains that these large fungi are likely not rare at all. He uses the word 'normal' to describe how they fit into the natural world, which directly completes the summary's final thought. |