Plants and microbes in UPSC Prelims: 19 questions, and six times the answer was 'all of them'

When aspirants prepare biodiversity, they usually start with animals: tigers, birds, the species in that year’s news. Plants, fungi and microbes get a quick read at the end, if at all. The past papers suggest they deserve more. UPSC has asked about them in 9 of the last 11 Prelims papers, and the questions are often easier to prepare for than the animal ones, because most of the answers sit in school biology.

This post looks at the 19 questions on plants and microbes and turns them into a plan.

What the numbers say

Three things stand out.

It rarely skips a year. Every paper from 2016 to 2026 had at least one question here, except 2017 and 2020. No paper had more than 3, and four papers (2016, 2018, 2021 and 2024) had exactly 3.

The news link has faded. Five questions said outright that the plant was in the news: a new wild banana, Red Sanders, Prosopis juliflora, the Himalayan nettle and Gucchi. All five came between 2016 and 2022. None of the 7 questions from 2023 to 2026 used a news cue. They asked about mushrooms, extremophile microbes, the pea family and plant forms instead.

The format followed the usual shift. Five questions in 2023, 2024 and 2025 used “How many of the above are correct?”. The 2025 question was a five-row table of plants and their forms. In 2026 UPSC went back to a classic statement set on the Foxtail orchid.

What UPSC is really testing

By our count, the 19 questions fall into five groups:

• Where a plant comes from: 5 questions. A new banana species found in the Andamans, Red Sanders in a part of South India, whether tamarind is native to South Asia, which of cashew, papaya and red sanders is native to India, and whether the Foxtail orchid is found only in the North-east.
• How plants live and spread: 5. Desert leaves that cut water loss, how plant diseases spread, which organisms grow on bare rock, the fig and its fig wasp, and Prosopis juliflora crowding out native plants.
• Fungi and microbes: 4. What viruses can infect, Gucchi (the morel mushroom), what mushrooms can do, and microbes that grow above boiling point or below freezing.
• Plant families and forms: 3. Which plants fix nitrogen, which belong to the pea family, and whether cassava, ginger, Malabar spinach, mint and papaya are shrubs, herbs or climbers.
• What a plant is used for: 2. The Himalayan nettle as a textile fibre and lemongrass as a mosquito repellent.

Some ideas keep coming back. Red Sanders appeared in 2016 and again in 2024. Legumes ran through three questions: moringa wrongly called leguminous in 2021, nitrogen-fixing plants in 2022, and the pea family in 2024. Papaya turned up in both 2024 and 2025.

The level of detail is low. No question needed a scientific name you had to recall, a number or a date. Eight of the 19 explanations on this site point to an NCERT chapter as the source.

The two traps UPSC keeps setting

Trap 1: the answer is “all of them”, and students hold back. Viruses can infect bacteria, fungi and plants. Desert plants use waxy leaves, tiny leaves and thorns. Birds, dust, rain and wind all spread plant diseases. All four mushroom statements were true, all three extremophile statements were true, and groundnut, horse-gram and soybean are all in the pea family. That is 6 of the 19 questions where every item listed was correct.

These statements are written with “some” (“Some mushrooms have bioluminescent properties”) or describe something that sounds impossible, like microbes growing above 100°C. Students cut the odd-sounding item to play safe, and lose the mark. When a statement only claims that some organism can do something, it is usually true.

The safe-looking answer is not always right, though. In the nitrogen-fixing question, only three of six plants were correct: alfalfa, chickpea and clover. Amaranth, purslane and spinach are leafy greens, not legumes.

Trap 2: common in India is not the same as native to India. Tamarind is in every Indian kitchen, but it comes from tropical Africa. Cashew came from Brazil and papaya from Central America. The Foxtail orchid is the state flower of Assam and Arunachal Pradesh, but it grows across South and South-east Asia. The Northeast is known for wild bananas, but the new species was found in the Andamans. Gucchi is famous and costly, but it is collected from the wild, not farmed.

When an option feels right because the plant is so familiar, ask where it actually started. That is where UPSC sets the trap.

How to prepare

1. Start with school biology, not the news. Read the NCERT chapters on biological classification, plant forms, nutrition and ecosystems. Viruses, fungi, extremophiles, legumes and ecological succession all come from there, and the recent papers have leaned that way.

2. Learn legumes properly. Know which common crops are legumes (chickpea, groundnut, horse-gram, soybean, alfalfa, clover) and which are not (moringa, amaranth, spinach). Know why it matters: legumes host bacteria in root nodules that fix nitrogen. This one idea has covered three questions.

3. Keep a “native or not” list. For each crop, fruit or tree that is widely grown in India, note where it came from. Cashew, papaya and tamarind came from elsewhere. Red Sanders is found only in a small part of South India. Add one line on whether the plant is endemic or just widespread.

4. Keep a plant notebook with four fields. For each plant that appears in the news, note:

• where it grows naturally, and whether it is found only there
• what kind of plant it is (tree, herb, climber, orchid, fungus)
• what it is used for, or why it is a problem
• what it is often confused with

The last field matters most. Lemongrass was set against Congress grass, elephant grass and nut grass. The fig was set against mahua, sandalwood and silk cotton.

5. Practise the “how many” questions. Judge each statement on its own, and don’t assume UPSC must have hidden a false one. In this area, “all of them” was the right answer six times.

What to skip: botanical families beyond the pea family, scientific names and production figures. None of the 19 questions needed them.

Two questions that show the pattern

2023 · Fungi and microbes. How many of four statements about mushrooms are correct? All four. Some mushrooms are medicinal, some are psychoactive, some kill insects and some glow in the dark. The glowing one sounds made up, which is exactly why students drop it. See the question

2024 · Where a plant comes from. How many of cashew, papaya and red sanders are native to India? Only one: red sanders. Cashew and papaya are grown so widely that they feel Indian, but both came from the Americas. See the question

For the animal side of this topic, see our post on species questions. You can also browse all biodiversity questions or the full list of must-do areas.