Question Discussion & Solution

The correct answer is option 3.

Concept:

A semaphore is a variable or abstract data type used to control access to a common resource by multiple threads and avoid critical section problems in a concurrent system such as a multitasking operating system.

Explanation:

Starvation is a problem that happens when high-priority processes continue to run while low priority processes are halted indefinitely. A continual stream of higher-priority processes in a densely loaded computer system can prevent a low-priority operation from ever receiving the CPU.

Indefinite blocking or starvation is a situation in which processes wait indefinitely within the semaphore. Indefinite blocking may occur if we remove processes from the list associated with a semaphore in LIFO (last-in, first-out) order.

Hence the correct answer is starvation.

Additional InformationCritical section:

 The critical section is the section of code in which processes access and write to shared resources such as common variables and files. Because processes run continuously, any process can be interrupted in the middle of its execution.

Concept-

• DNA stands for Deoxyribonucleic acid.
• DNA as an acidic substance present in the nucleus was first identified by Friedrich Meischer in 1869.
• He named it ‘Nuclein’.
• DNA acts as the genetic material in most organisms.
• A DNA molecule consisting of all the genetic material of an organism is known as a chromosome.
• These are thread-like (helical) structures of protein and nucleic acids which​ carry all the genetic information in the form of genes.

Explanation-

• ​Deoxyribonucleic acid (DNA) is a nucleic acid and is therefore made up of nucleotide.
• Each nucleotide consists of a phosphate group, a nitrogenous base (A, T, G, C), and ribose sugar (deoxyribose in case of DNA).
• A nucleoside contains only pentose sugar and a nitrogenous base.
• Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are the two types of nucleic acids found in living systems.
• DNA is a long polymer of deoxyribonucleotides.
• The length of DNA is usually defined as the number of nucleotides (or a pair of nucleotides referred to as base pairs) present in it.

Thereby DNA is composed only of nucleic acid.

Additional Information

Lipids: 

• ​These organic compounds are nonpolar molecules, which are soluble only in nonpolar solvents and insoluble in water because water is a polar molecule.
• In the human body, these molecules can be synthesized in the liver and are found in oil, butter, whole milk, cheese, fried foods, and also in some red meats.

Proteins:

• Proteins are composed of amino acids, arranged into different groups.
• These fundamental amino acid sequences are specific and their arrangements are controlled by the DNA. 
• These are the fundamental building blocks of our bodies.
• They are large and complex macromolecules or bio-molecules which perform a major role in the functioning and regulating of our body cells, tissues, and other organs in the human body.​

The correct answer is Kanhaiya Lal Sethiya.

• Kanhaiyalal Sethia was a well-known Rajasthani and Hindi poet born in Sujangarh, Churu District of Rajasthan.
  • His "Dharti Dhoran Ri" is recognized as the anthem song of Rajasthan throughout the world. 

Additional Information

• Chandra Prakash Deval is a Rajasthani poet and translator. He is also the convener of Rajasthani Advisory Council of Sahitya Akademi.
  • He has received Padma Shri in 2011, the fourth highest civil honour given by the Government of India.
• Dr Bhagwati Lal Vyas was awarded Bihari Puraskar in 2015 for his anthology of Rajasthani poems ‘Katha Sun Aawe Hai Sabad’ published in 2010.
• Vijaydan Detha, also known as Bijji, was a noted Indian writer of Rajasthani literature.
  • He was a recipient of several awards including the Padma Shri and the Sahitya Akademi Award.

Rajendra Prasad is the first president of India. Similarly, the first president of USA is George Washington.

Hence, George Washington is the correct answer.

The correct answer is 4°C.

• Freezing of Water:
  • As water freezes, cold water (or ice formed) comes on the surface and warm water goes down.
  • Since the freezing temperature of the water is 0ºC or 273 K.
  • So water at the bottom should be at a higher temperature.
  • Water density at 4ºC is more than the density of water at 0ºC, hence the correct option is 4ºC.

​Key Points

• Reason of low temperature at bottom of the top layer:
  • This is due to the process of convection.
  • When the temperature of the water at the top layer reaches the freezing point, it is converted to ice.
  • But ice is lighter than water, so it will not sink to the bottom.
  • So there will be ice on the top surface and water would remain at the bottom of the lake.