Question Discussion & Solution

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. 

The correct answer is about 70% water.

Important Points

• The Top Four Elements Found in the Human Body: oxygen (65%), carbon (18.5%), hydrogen (9.5%), nitrogen (3.2%).
• The other trace elements (less than 0.01%) are boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), fluorine (F), iodine (I), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se), silicon (Si), tin (Sn), vanadium (V), and zinc (Zn).
• The six major nutrients are carbohydrates (CHO), lipids (fats), proteins, vitamins, minerals, water.
• The functions of water in the human body:
  • Water carries nutrients and oxygen to all cells in the body.
  • Water is required for breathing.
  • Water regulates your body temperature.
  • Water protects and cushions vital organs.
  • Water cushions joints.
  • Water removes waste.

Key Points

• Calcium (Ca) is the most abundant mineral in the body and is essential for a number of vital functions.
  • Also helps muscles relax and contract, important in nerve functioning, blood clotting, blood pressure regulation, immune system health.
• Iron (Fe), Part of a molecule (haemoglobin) found in red blood cells that carries oxygen in the body, needed for energy metabolism.
• Iodine found in thyroid hormone, which helps regulate growth, development, and metabolism.
• Chromium works closely with insulin to regulate blood sugar (glucose) levels.

Important functions of a database administrator are:

• Schema definition schema and physical organization modification granting of authorization for data access
• Monitoring jobs running on the database and ensuring that performance is not degraded by very expensive tasks submitted by some users.
• Routine maintenance includes activities like periodic ensuring that backup and enough freedisk space is available for normal operations and upgrading disk space as required.

The correct answer is Fermentation.

Key Points

• Fermentation:
  • The biological process, in which sugar molecules are converted into ethyl alcohol and carbon dioxide with the help of some microbes like yeast and bacteria is called alcohol fermentation.
  • It is an anaerobic process. i.e. it occurs in the absence of oxygen.
  • The process is governed by the enzyme alcohol dehydrogenase
  • Alcoholic fermentation has many uses such as for the production of alcoholic beverages, ethanol fuel, and bread cooking.

Additional Information

• Moulding:
  • ​Moulding is a typical process in which a type of fungus that grows surface of fruits and vegetable.
  • These tubular branches have multiple, genetically identical nuclei, yet form a single organism, known as a colony.
  • In contrast, yeast is a type of fungus that grows as a single cell.
• Nitrogen Fixation:
  • Nitrogen fixation is the chemical process by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle. 
  • Atmospheric nitrogen is fixed by several methods like biological N2 fixation, Industrial N2 fixation & Electrical N2 fixation.
  • It is a necessary process, as the fixed nitrogen is used in the biosynthesis of several organic compounds like amino acids, proteins, nucleic acids, etc.
• Transcription:
  • ​The process of copying genetic information from one strand of DNA into RNA is termed transcription or mRNA synthesis.
  • The process of transcription begins when an enzyme called RNA polymerase attaches to the template DNA strand and begins to catalyze the production of complementary RNA.
  • It is completed in three steps Initiation, Elongation & Termination.

The correct answer is Drag and Drop.

• The action of using the mouse to move an item on the computer screen to a new location is called Drag and Drop.
• Drag and drop is a common action performed within a graphical user interface that involves moving the cursor over an object, selecting it, and moving it to a new location.
• While using a mouse, we can drag and drop an object by clicking the mouse button to select an object, then moving the mouse while keeping the mouse button pushed down. This is called "dragging" the object.
• After moving the object where we want to place it, we can lift up the mouse button to "drop" the object in the new location. 
• Copy and paste are commands in a computer user interface and are one method of transferring data from one location to another. It creates a duplicate in the new location and enables simple data replication.
• Cut removes the item from its current location and places it into the clipboard. Paste inserts the current clipboard contents into the new location.
• Plug and Play is a phrase used to describe devices that work with a computer system as soon as they are connected.