Question Discussion & Solution

Given: 40 × 20 ÷ 28 - 4 + 2

The logic follows here is: 

  
By inserting codes and then using BODMAS Rule:

40 + 20 - 28 ÷ 4 × 2

= 40 + 20 - 7 × 2

= 40 + 20 - 14 

= 60 - 14

= 46

Hence, 46 is the correct answer.

Flood is overflow of water. In the same way, drought is a continuous dry period of weather.

Explanation:

• Evolutionary biology: It is a field of science that deals with the study of evolutionary processes like natural selection, speciation & common descent that has led to the diversification of life on earth.
• Charles Darwin is known as the father of ''Evolutionary Biology''.
• Darwin proposed a theory of evolution called natural selection in the year 1859. According to it those populations which are a better fit (reproductively fit) in an environment will be selected by nature and will survive more.
• Charles Darwin wrote a book named ''The origin of species'' which is considered to be the foundation of evolutionary biology.

Additional Information 

• Herbert Spencer- He Was best known for the introduction and application of evolutionary theory to philosophy, psychology, and social sciences
• The famous phrase 'Survival of the fittest' to mean Natural Selection was coined by Herbert Spencer. He originated this phrase after the publication of famous biologist Charles Darwin’s book ‘Origin of Species’ which talked about ‘Natural Selection’.
• Julian Huxley was an English biologist, philosopher, educator, and author who greatly influenced the modern development of embryology, systematics, and studies of behaviour and evolution.
• Stanley Miller along with H.C. Urey provided experimental evidence of ''chemical evolution''

Explanation:- 

• Oxidation is a chemical reaction in which oxygen is added to a substance or hydrogen is removed from the substance. The oxidizing agent is the chemical compound that provides oxygen or removes hydrogen from the reactants. Oxidizing agents are also known as Oxidant or Oxidizer. 
• Here, Aluminium is the only metal that forms a protective layer of its own oxide Al₂O₃. This Aluminium Oxide layer serves as a barrier and prevents the element Aluminium from further corrosion.

Additional Information

•  Gold (Au):- Gold is a noble metal, it belongs to group 11 and it is least reactive. It shows +1 and +3 oxidation states.
• Silver (Ag):-  It is a white lustrous element of group 11. Being a noble metal it is less reactive in nature. Silver is a good conductor of electricity.
• Aluminum (Al):- Aluminium is a metal from group 13, It is a light-weighted silvery metal with 3+ valency. Common Oxidation states shown by Aluminium is +1, +2, +3. 
• Iron (Fe):- Iron is a highly reactive metal, It reacts with the oxygen present in the air very easily and forms Iron oxides like FeO, Fe₂O_3, Therefore, Iron undergoes rusting

 .Hint :- Au, Ag, both are  less reactive in nature, Iron is highly reactive, whereas Al is reactive in nature but doesn't react with air due to the formation of Al₂O₃ 

The correct answer is Vitamin B1.

Key Points

• When rice is produced and not polished it is called brown rice. 
• Brown rice is rich in Vitamin B1. 
• When brown rice is polished, rice loses many vitamins and minerals including Vitamin B1 through the bran.
• Vitamin B1 also called thiamine is an essential vitamin, a deficiency of which is known to cause beriberi.

Additional Information