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Q1. Apart from carbohydrates, plants also synthesize: NCERT
ā¢ Only vitamins
ā¢ Proteins and fats
ā¢ Only minerals
ā¢ Only water
Answer: Proteins and fats
Plants are capable of synthesizing all the organic compounds they need, including carbohydrates, proteins, and fats, from basic raw materials .
Q2. Plants use carbohydrates along with nitrogen and other elements to synthesize: Science
ā¢ Fats
ā¢ Proteins
ā¢ Starch
ā¢ Cellulose
Answer: Proteins
Proteins are made by combining carbohydrates with nitrogen and sometimes sulfur. Plants absorb nitrogen from the soil in the form of soluble compounds .
Q3. The element essential for protein synthesis that plants obtain from soil is: NCERT
ā¢ Carbon
ā¢ Oxygen
ā¢ Nitrogen
ā¢ Hydrogen
Answer: Nitrogen
Nitrogen is a crucial component of amino acids, which are the building blocks of proteins. Plants absorb nitrogen from the soil .
Q4. Fats and oils in plants are synthesized from: Science
ā¢ Proteins
ā¢ Minerals
ā¢ Carbohydrates
ā¢ Vitamins
Answer: Carbohydrates
Plants convert excess carbohydrates into fats and oils for storage. This is why seeds like groundnut, mustard, and sunflower are rich in oils .
Q5. Which part of a plant typically stores the most fats and oils? NCERT
ā¢ Leaves
ā¢ Roots
ā¢ Seeds
ā¢ Stems
Answer: Seeds
Seeds are storage organs for the next generation. They store fats and oils as an energy reserve for the germinating seedling .
Q6. Plants that lack chlorophyll and obtain their nutrition from other organisms are called: NCERT
ā¢ Autotrophs
ā¢ Heterotrophs
ā¢ Producers
ā¢ Green plants
Answer: Heterotrophs
Non-green plants cannot perform photosynthesis, so they depend on other organisms for food and are classified as heterotrophs .
Q7. An organism that lives on or inside another living organism and derives food from it is called a: NCERT
ā¢ Host
ā¢ Parasite
ā¢ Saprotroph
ā¢ Symbiont
Answer: Parasite
A parasite is an organism that lives on or inside a host organism and obtains its nutrition at the expense of the host .
Q8. The organism from which a parasite derives its food is called the: NCERT
ā¢ Predator
ā¢ Prey
ā¢ Host
ā¢ Saprophyte
Answer: Host
The host is the living organism that provides shelter and nutrients to the parasite. The host is harmed in this relationship .
Q9. Cuscuta (Amarbel) is an example of a: NCERT
ā¢ Saprophyte
ā¢ Autotroph
ā¢ Parasite
ā¢ Symbiont
Answer: Parasite
Cuscuta has no chlorophyll and twines around the host plant, inserting special roots (haustoria) into the host’s tissues to absorb ready-made food .
Q10. Plants that feed on insects are called: NCERT
ā¢ Parasitic plants
ā¢ Saprophytic plants
ā¢ Insectivorous plants
ā¢ Symbiotic plants
Answer: Insectivorous plants
Insectivorous plants are specialized plants that trap and digest insects to obtain nitrogen, as they grow in nitrogen-deficient soils .
Q11. The pitcher plant gets its name because: Science
ā¢ It stores water in a pitcher
ā¢ Its leaf is modified into a pitcher-like structure to trap insects
ā¢ It looks like a pitcher
ā¢ It grows near water pitchers
Answer: Its leaf is modified into a pitcher-like structure to trap insects
In pitcher plants, the leaf is modified into a pitcher-like structure with a lid that traps insects. The insect gets digested inside this pitcher .
Q12. Why do insectivorous plants trap insects? NCERT
ā¢ For food (carbohydrates)
ā¢ For water
ā¢ For nitrogen deficiency
ā¢ For oxygen
Answer: For nitrogen deficiency
Insectivorous plants grow in soil deficient in nitrogen. They trap and digest insects to fulfill their nitrogen requirement for protein synthesis .
Q13. Which of the following is an insectivorous plant? NCERT
ā¢ Cactus
ā¢ Mango
ā¢ Venus flytrap
ā¢ Cuscuta
Answer: Venus flytrap
The Venus flytrap is a well-known insectivorous plant. Its leaves snap shut when an insect touches sensitive hairs on their surface .
Q14. Organisms that obtain nutrition from dead and decaying matter are called: NCERT
ā¢ Parasites
ā¢ Predators
ā¢ Saprotrophs
ā¢ Hosts
Answer: Saprotrophs
Saprotrophs are organisms that feed on dead and decaying organic matter. They secrete digestive juices on the food and absorb the dissolved nutrients .
Q15. Which of the following is an example of a saprotroph? NCERT
ā¢ Mango tree
ā¢ Bread mold (fungus)
ā¢ Cuscuta
ā¢ Tiger
Answer: Bread mold (fungus)
Bread mold is a fungus that grows on dead organic matter like bread. It secretes enzymes to digest the bread and then absorbs nutrients .
Q16. The mode of nutrition in fungi is: NCERT
ā¢ Autotrophic
ā¢ Parasitic
ā¢ Saprotrophic
ā¢ Insectivorous
Answer: Saprotrophic
Most fungi are saprotrophs. They decompose dead organic matter and absorb nutrients from it .
Q17. Saprotrophs secrete digestive juices on: Science
ā¢ Living organisms
ā¢ Dead and decaying matter
ā¢ Green plants
ā¢ Rocks
Answer: Dead and decaying matter
Saprotrophs release digestive enzymes onto dead matter to break it down into simpler substances, which are then absorbed .
Q18. Mushrooms growing on a rotting log are examples of: NCERT
ā¢ Parasites
ā¢ Autotrophs
ā¢ Saprotrophs
ā¢ Insectivorous plants
Answer: Saprotrophs
Mushrooms are fungi that decompose the dead wood of the log and obtain their nutrition from it .
Q19. The association where two different organisms live together and mutually benefit each other is called: NCERT
ā¢ Parasitism
ā¢ Saprotrophism
ā¢ Symbiosis
ā¢ Predation
Answer: Symbiosis
Symbiosis is a close, long-term interaction between two different biological organisms where both are benefitted .
Q20. Lichen is a symbiotic association between: NCERT
ā¢ Fungus and root
ā¢ Alga and fungus
ā¢ Bacteria and plant
ā¢ Virus and alga
Answer: Alga and fungus
Lichen consists of an alga (or cyanobacterium) and a fungus. The alga prepares food, and the fungus provides shelter and absorbs water and minerals .
Q21. In lichen, what does the alga provide to the fungus? Science
ā¢ Water
ā¢ Minerals
ā¢ Food (carbohydrates)
ā¢ Shelter
Answer: Food (carbohydrates)
The algal component (phycobiont) contains chlorophyll and performs photosynthesis, producing food that is shared with the fungal component (mycobiont).
Q22. In lichen, what does the fungus provide to the alga? Science
ā¢ Food
ā¢ Chlorophyll
ā¢ Water, minerals, and shelter
ā¢ Carbon dioxide
Answer: Water, minerals, and shelter
The fungal component absorbs water and minerals from the surroundings and provides a protective structure for the alga to live in .
Q23. Rhizobium bacteria live in the root nodules of: NCERT
ā¢ Wheat plants
ā¢ Rice plants
ā¢ Leguminous plants (like peas, beans)
ā¢ All plants
Answer: Leguminous plants (like peas, beans)
Rhizobium bacteria form a symbiotic association with leguminous plants like gram, peas, moong, beans, and clover .
Q24. The relationship between Rhizobium and leguminous plants is an example of: NCERT
ā¢ Parasitism
ā¢ Saprotrophism
ā¢ Symbiosis
ā¢ Insectivorous
Answer: Symbiosis
It is a mutually beneficial relationship. The plant provides food and shelter to the bacteria, and the bacteria provide nitrogen to the plant .
Q25. Rhizobium bacteria convert atmospheric nitrogen into a form that plants can use. This process is called: Science
ā¢ Photosynthesis
ā¢ Transpiration
ā¢ Nitrogen fixation
ā¢ Respiration
Answer: Nitrogen fixation
Nitrogen fixation is the process of converting atmospheric nitrogen (Nā) into compounds like ammonia that plants can absorb and use .
Q26. Plants cannot absorb atmospheric nitrogen directly because: Science
ā¢ It is too heavy
ā¢ It is in an unusable form
ā¢ They don’t need nitrogen
ā¢ It is present in very small amounts
Answer: It is in an unusable form
Atmospheric nitrogen (Nā) is very stable and inert. Plants cannot break the triple bond between nitrogen atoms, so they need it “fixed” into soluble compounds .
Q27. Continuous growing of crops in the same field makes the soil poor in: NCERT
ā¢ Water
ā¢ Air
ā¢ Nutrients
ā¢ Sand
Answer: Nutrients
Repeated cropping (growing the same crop) year after year in the same field depletes specific nutrients from the soil that those crops require .
Q28. Nutrients in the soil are replenished by adding: NCERT
ā¢ Water only
ā¢ Fertilizers and manure
ā¢ Pesticides
ā¢ Weeds
Answer: Fertilizers and manure
To restore soil fertility, farmers add fertilizers (chemicals) or manure (organic matter) that contain essential nutrients like nitrogen, phosphorus, and potassium .
Q29. Which bacteria present in root nodules help in nitrogen fixation? NCERT
ā¢ E. coli
ā¢ Lactobacillus
ā¢ Rhizobium
ā¢ Streptococcus
Answer: Rhizobium
Rhizobium bacteria are the nitrogen-fixing bacteria that live symbiotically in the root nodules of leguminous plants .
Q30. Farmers rotate crops by growing legumes in the field to: Science
ā¢ Get more vegetables
ā¢ Increase water content
ā¢ Replenish nitrogen in the soil
ā¢ Prevent pests
Answer: Replenish nitrogen in the soil
Legumes have Rhizobium in their roots, which fix nitrogen. When the crop is harvested or plowed back, it enriches the soil with nitrogen for the next crop .
Q31. Parasitic plants absorb ready-made food from the host through special structures called: NCERT
ā¢ Root hairs
ā¢ Stomata
ā¢ Haustoria
ā¢ Pneumatophores
Answer: Haustoria
Haustoria are specialized, root-like structures that penetrate the host plant’s tissues to draw water and nutrients .
Q32. Indian pipe (Monotropa) is a plant that lacks chlorophyll and gets food from dead matter. It is a: Science
ā¢ Parasite
ā¢ Saprophyte
ā¢ Insectivorous plant
ā¢ Autotroph
Answer: Saprophyte
Indian pipe (Monotropa uniflora) is a non-green plant that obtains its nutrition from decaying organic matter in the soil with the help of associated fungi .
Q33. Which of the following is a partial parasite that performs photosynthesis but also derives water and minerals from the host? Science
ā¢ Cuscuta
ā¢ Mistletoe
ā¢ Mushroom
ā¢ Pitcher plant
Answer: Mistletoe
Mistletoe has green leaves and can perform photosynthesis, but it sends its roots into the host tree to absorb water and minerals. It is called a partial parasite .
Q34. The rotting dead matter on which saprotrophs grow is called: Science
ā¢ Humus
ā¢ Substrate
ā¢ Host
ā¢ Prey
Answer: Substrate
The dead and decaying material on which saprotrophs grow and derive nutrition is known as the substrate .
Q35. Enzymes secreted by saprotrophs help in: Science
ā¢ Photosynthesis
ā¢ Digesting complex food into simpler forms
ā¢ Reproduction
ā¢ Transpiration
Answer: Digesting complex food into simpler forms
Saprotrophs release digestive enzymes onto dead matter to break down complex organic compounds into simpler, absorbable forms .
Q36. The mode of nutrition in animals and most non-green plants is: NCERT
ā¢ Autotrophic
ā¢ Heterotrophic
ā¢ Photosynthetic
ā¢ Chemosynthetic
Answer: Heterotrophic
Animals and non-green plants cannot synthesize their own food. They depend on other organisms for nutrition, hence they are heterotrophs .
Q37. A symbiotic association in which both organisms are benefitted is called: NCERT
ā¢ Mutualism (Mutually beneficial symbiosis)
ā¢ Commensalism
ā¢ Parasitism
ā¢ Predation
Answer: Mutualism (Mutually beneficial symbiosis)
When symbiosis benefits both partners, it is specifically called mutualism. Lichen and Rhizobium-legume are examples .
Q38. The element that is fixed by Rhizobium in leguminous plants is: NCERT
ā¢ Oxygen
ā¢ Carbon
ā¢ Nitrogen
ā¢ Hydrogen
Answer: Nitrogen
Rhizobium bacteria fix atmospheric nitrogen into soluble nitrogenous compounds that plants can use for protein synthesis .
Q39. Which of the following is NOT a method to replenish soil nutrients? Science
ā¢ Adding fertilizers
ā¢ Adding manure
ā¢ Crop rotation
ā¢ Continuous monoculture
Answer: Continuous monoculture
Growing the same crop continuously (monoculture) depletes nutrients. Methods like adding fertilizers, manure, and crop rotation replenish them .
Q40. The practice of growing different crops alternately to replenish soil nutrients is called: NCERT
ā¢ Multiple cropping
ā¢ Crop rotation
ā¢ Intercropping
ā¢ Hybridization
Answer: Crop rotation
Crop rotation involves growing different types of crops (like legumes followed by wheat) in the same field in a sequenced manner to restore soil fertility .
Q41. Which nutrient is most commonly replenished by growing leguminous crops? Science
ā¢ Phosphorus
ā¢ Potassium
ā¢ Nitrogen
ā¢ Calcium
Answer: Nitrogen
Legumes, with the help of Rhizobium, fix atmospheric nitrogen, thereby enriching the soil with nitrogen compounds .
Q42. Manure is better than fertilizers because it: Science
ā¢ Acts faster
ā¢ Is cheaper and improves soil structure
ā¢ Contains more nitrogen
ā¢ Is easy to transport
Answer: Is cheaper and improves soil structure
Manure is organic, improves soil texture, increases water holding capacity, and adds humus, unlike chemical fertilizers which only add nutrients .
Q43. The process of nitrogen fixation by Rhizobium occurs in: Science
ā¢ Leaves
ā¢ Stems
ā¢ Root nodules
ā¢ Flowers
Answer: Root nodules
Root nodules are specialized structures on the roots of leguminous plants where Rhizobium bacteria live and fix nitrogen .
Q44. A plant that partially depends on another plant for shelter and nutrition is called a: NCERT
ā¢ Total parasite
ā¢ Partial parasite
ā¢ Saprophyte
ā¢ Autotroph
Answer: Partial parasite
Partial parasites like mistletoe have chlorophyll and perform photosynthesis but depend on the host for water and minerals .
Q45. Which of the following contains chlorophyll but still depends on other plants? Science
ā¢ Cuscuta
ā¢ Mushroom
ā¢ Mistletoe
ā¢ Pitcher plant
Answer: Mistletoe
Mistletoe has green leaves (contains chlorophyll) but derives water and minerals from the host tree, making it a partial parasite .
Q46. Fungi like yeast which grow on dead sugary substances are examples of: Science
ā¢ Parasites
ā¢ Saprotrophs
ā¢ Autotrophs
ā¢ Insectivores
Answer: Saprotrophs
Yeast feeds on dead and decaying sugary substances by secreting enzymes and absorbing nutrients, hence it is a saprotroph .
Q47. The relationship between a shark and a remora fish (which attaches to shark and eats leftovers) is an example of: Science
ā¢ Parasitism
ā¢ Symbiosis
ā¢ Commensalism (one benefits, other unaffected)
ā¢ Saprotrophism
Answer: Commensalism (one benefits, other unaffected)
Commensalism is a type of relationship where one organism benefits while the other is neither helped nor harmed. Remora benefits from shark’s leftovers.
Q48. The root nodules of leguminous plants contain a pigment called: Science
ā¢ Chlorophyll
ā¢ Haemoglobin
ā¢ Leghemoglobin
ā¢ Carotene
Answer: Leghemoglobin
Leghemoglobin is a pinkish pigment found in root nodules that protects the nitrogen-fixing enzyme (nitrogenase) from oxygen .
Q49. Which element is essential for making proteins and is often deficient in soil? NCERT
ā¢ Carbon
ā¢ Hydrogen
ā¢ Nitrogen
ā¢ Oxygen
Answer: Nitrogen
Nitrogen is a key component of amino acids and proteins. It is often depleted from soil and needs replenishment through fertilizers, manure, or crop rotation .
Q50. The ultimate source of nitrogen for plants is: Science
ā¢ Soil
ā¢ Fertilizers
ā¢ Atmosphere
ā¢ Water
Answer: Atmosphere
The atmosphere is about 78% nitrogen gas. However, plants cannot use it directly. They depend on nitrogen-fixing bacteria to convert atmospheric nitrogen into usable forms .