Q.1
Where can nitrogen fixing bacteria be found
  • Free living in the soil
  • living on the nodules of certain plants
  • in the atmosphere
  • Both A & B
Q.2
Fixation is the process of
  • conversion of N2 to forms that can be used to synthesize inorganic nitrogen compounds
  • conversion of Co2 to forms that can be used to synthesize organic carbonic compounds
  • conversion of N2 to forms that can be used to synthesize organic nitrogen compounds
  • conversion of H2O to forms that can be used to synthesize organic aqueous compounds
Q.3
Nitrogen fixation is the
  • Conversion of N2(nitrogen) to NO3-(nitrate)
  • Conversion of N2 to N
  • Conversion of N2 to urea
  • All of the above
Q.4
What plants help or are beneficial to the nitrogen cycle?
  • peas
  • clover
  • peanuts
  • All Of above
Q.5
What do free living bacteria in the soil do?
  • Make clouds
  • Turn atmospheric nitrogen into nitrates
  • Make carbon dioxide for plants to go through photosynthesis
  • Help plants take in water
Q.6
Which plant is an example of a legume?
  • strawberries
  • carrots
  • peanuts
  • corn
Q.7
What can excess amounts of nitrogen cause in ecosystems?
  • Disrupts the equilibrium of ecosystem, causing number of species to decline
  • Leads to improvement of an ecosystem due to healthy plant growth
  • Leads to high oxygen content in aquatic ecosystems
  • Increases the speed of decomposition of plants and animals
Q.8
How does fertilizer affect the nitrogen cycle
  • cause nitrous oxide, a greenhouse gas, to enter the atmosphere and trap heat
  • create large algae blooms in the water
  • cause the nitrogen fixing bacteria in the soil to be less productive
  • All Of above
Q.9
Burning fossil fuels releases this into the air
  • nitrous oxide
  • nitrate
  • nitrogen gas (N2)
  • methane
Q.10
Plants and animals need nitrogen to make __________.
  • Protein
  • Carbohydrates
  • Lipids
  • Minerals
Q.11
What is the formula for atmospheric nitrogen?
  • N
  • N2
  • NH3
  • NO3
Q.12
Nitrogen accounts nearlyof the air. Still Nitrogen is the most limiting nutrient for plant growth because
  • N2 cannot be directly utilized by plants
  • High energy is required to break triple bond
  • Nitrogen is almost an inert gas as N involved reaction requires extreme conditions such as high temperature
  • All of the above
Q.13
What is the process of combining nitrogen gas with other elements to make nitrogen into usable compounds?
  • nitrogen composition
  • ammonia
  • nitrogen fixation
  • denitrification
Q.14
What is the role of denitrifying bacteria
  • change nitrate back into nitrogen gas
  • change nitrogen gas into nitrate
  • absorb carbon dioxide in the soil
  • release oxygen gas into the atmosphere
Q.15
Bacteria fix nitrogen from the atmosphere into a form plants can use.
  • True
  • False
Q.16
Arrange the following process of nitrogen cycle in proper sequence (i)Denitrification(ii)Nitrogen Fixation(iii)Ammonification(iv)Nitrification
  • i-iii-iv-i
  • i-ii-iii-iv
  • iv-iii-ii-i
Q.17
Nitrogen-rich fertilizers and manure can cause water pollution.
  • True
  • False
Q.18
What happens when organisms die and decay?
  • Their bodies are lifted up
  • Their nitrogen returns to the soil
  • they keep their nitrogen
  • They stay on earth forever
Q.19
Can animals and plants directly absorb nitrogen from the atmosphere, is this statement true or false
  • False
  • True
Q.20
Round structures on the roots of certain plants
  • lichens
  • commensals
  • cataracts
  • nodules
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