21.

Which one of the following is used as preservative?

• Sodium benzoate
  
  

• Ammonium sulphate
  
  

• Sodium chloride
  
  

• Copper sulphate

Which one of the following is a step of analogy strategy in science?

• Presentation of abstraction
  
  

• Interlinking concepts
  
  

• Application
  
  

• Map similarities

Yeast is used for the production of

• curd
  
  

• sugar
  
  

• common salt
  
  
  

• alcohol 

Mitochondria: ATP:: Ribosome?

• Fat
  
  

• Protein
  
  

• Vitamin
  
  

• Carbohydrate

If the frequency of a simple pendulum is 2 Hz, how many oscillations will it complete in 16s?

• 16

• 64

• 32
  
  

• 8

Which one of the following metals burns, if kept in air?

• Magnesium
  
  

• Aluminum
  
  

• Zinc
  
  

• Sodium

Magnesium hydroxide (Mg (OH)₂) is used as

• reducing agent
  
  

• anti-acid
  
  

• fermentation agent
  
  

• oxidising agent

Which one of the following gases burn with pop sound?

• Hydrogen

• Nitrogen dioxide
  
  

• Sulphur dioxide
  
  

• Oxygen
  
  

Which of the following is/are example(s)of non-contact force?

• Muscular force
  
  

• Gravitation force
  
  

• Magnetic force
  
  

• Both (A) and (B)

Diabetes is controlled by which hormone?

• Adrenaline
  
  

• Insulin
  
  

• Thymosin
  
  

• Thyroxine