How do microorganisms help the environment, according to the text?
  • By cleaning the environment through breaking down waste
  • By causing diseases in plants
  • By making the soil dry
  • By stopping plant growth
What does the word ‘Krimi’ in ancient Indian texts refer to?
  • Different tiny entities, both visible and invisible
  • Only large animals
  • Only plants
  • Only rocks and minerals
Why is manure formation important for plants?
  • It returns important nutrients to the soil, helping plants grow better
  • It makes the soil hard and dry
  • It attracts insects that harm plants
  • It prevents water from reaching plant roots
What can we infer from Activity 2.7 about microorganisms?
  • They help in plant growth and clean the environment by breaking down waste
  • They only cause diseases
  • They are harmful to all living things
  • They do not affect the environment
Which gas is primarily produced by microorganisms during the decomposition of plant and animal waste in an oxygen-free environment?
  • Oxygen
  • Methane
  • Nitrogen
  • Hydrogen
What is biogas mainly composed of?
  • Carbon monoxide and oxygen
  • Carbon dioxide and methane
  • Nitrogen and hydrogen
  • Oxygen and methane
What is the main use of biogas produced by microorganisms?
  • As a fertilizer
  • As a fuel source for cooking, heating, and generating electricity
  • As a cleaning agent
  • As a medicine
Who developed a special bacterium that could break down oil spills in 1971?
  • Albert Einstein
  • Ananda Mohan Chakrabarty
  • Marie Curie
  • Isaac Newton
What is a patent?
  • A scientific theory
  • A copyright given to a person so that no one else can copy, use, or sell their invention without permission
  • A type of microorganism
  • A method of producing biogas
Why was Ananda Mohan Chakrabarty’s work important for the environment?
  • He invented a new type of fuel
  • He developed a bacterium that helped clean oil spills
  • He discovered a new planet
  • He created a new type of food
In Activity 2.8, what is the purpose of adding yeast powder to bowl A but not to bowl B?
  • To make the dough taste better
  • To compare the effect of yeast on the dough
  • To make the dough harder
  • To change the color of the dough
What is the next step after mixing flour and sugar in both bowls during Activity 2.8?
  • Add water to both bowls
  • Knead the flour of the two bowls with warm water to make soft dough
  • Bake the dough
  • Freeze the dough
What environmental problem did Ananda Mohan Chakrabarty’s invention help solve?
  • Air pollution
  • Oil spills
  • Water scarcity
  • Deforestation
What is the significance of comparing the results of two bowls in Activity 2.8?
  • To see which bowl is heavier
  • To observe the effect of yeast on dough formation
  • To find out which bowl has more sugar
  • To check the color change in the dough
What is the main reason dough rises and becomes fluffy when yeast is added?
  • Yeast produces carbon dioxide which forms bubbles in the dough.
  • Yeast absorbs water and expands the dough.
  • Yeast makes the dough heavier.
  • Yeast changes the color of the dough.
To test curd formation, why is it important to keep one bowl of milk in a warm place and the other in a cool place?
  • To see how temperature affects curd formation.
  • To make the milk taste different.
  • To change the color of the milk.
  • To make the milk boil faster.
Which group of microorganisms does yeast belong to?
  • Fungi
  • Bacteria
  • Viruses
  • Algae
What is the special property of yeast that is used in making breads, cakes, and other foods?
  • Yeast produces carbon dioxide and alcohol, making dough soft and fluffy.
  • Yeast changes the color of the dough.
  • Yeast makes the dough hard.
  • Yeast cools the dough.
Which part of the cell controls all its activities?
  • Cell membrane
  • Cytoplasm
  • Vacuole
  • Nucleus
Which of the following is present only in plant cells?
  • Nucleus
  • Cytoplasm
  • Chloroplast
  • Cell membrane
Which cell helps in transmitting messages in the body?
  • Nerve cell
  • Blood cell
  • Skin cell
  • Muscle cell
Microorganisms in soil help in:
  • Polluting soil
  • Decomposing waste
  • blocking nutrients
  • Drying soil
A student compared two cells:Cell A: Has cell wall and chloroplastCell B: Has no cell wallWhich statement is correct?
  • Both are plant cells
  • Both are animal cells
  • Cell A is plant cell and Cell B is animal cell
  • Cell A is animal cell and Cell B is plant cell
Identify the micro organism
  • Amoeba
  • Paramecium
  • Mould
  • Algae
Which of the following microorganisms is commonly found in pond water?
  • Amoeba
  • Tiger
  • Earthworm
  • Lizard
Which Scientist discovered the cell?
  • Antonie Van Leeuwenhoek
  • Alan Turing
  • Robert Boyle
  • Robert Hooke
What is the function of the cell membrane ?
  • Control the activities of the cell
  • Gives shape to the cell
  • Produces energy
  • Controls entry and exit of substances
Why is glycerin added while preparing a temporary slide of an onion cell?
  • To increase the size of the cell
  • To keep the cell moist and prevent it from drying
  • To dissolve the cell wall
  • To stain the cell and make it colorful
1. The Andromeda Galaxy is the nearest spiral galaxy to the Milky Way Galaxy. Which unit would best be used to represent the distance between the Milky Way Galaxy and the Andromeda Galaxy?
  • astronomical unit
  • kilometer
  • light year
  • mile
Rachel is learning about electromagnetic radiation that comes from the sun. What types of electromagnetic radiation does the sun emit?
  • gamma rays and ultraviolet radiation
  • ultraviolet radiation only
  • infrared, visible, and ultraviolet radiation
  • all types of electromagnetic radiation
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