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The correct answer is 3 i.e. Propyne.

Example:

• This hydrocarbon contains 3 carbon atoms which are indicated by writing 'prop'.
• This hydrocarbon has a carbon-carbon triple bond so it is unsaturated.
• The triple bond is indicated by using the ending 'yne'.
• Now, by combining, 'prop' and 'yne', the IUPAC name of the above hydrocarbon becomes; 'propyne'.
• The IUPAC name of the unsaturated hydrocarbon containing 3 carbon atoms and a triple end is propyne.
• Please note that the name of an alkyne is derived from the name of the corresponding alkane by replacing the suffix ane by yne.
• The common name of propyne is Methyl-acetylene (C3H₄).

The correct answer is Calcium sulfate and water.

• The acid-base reaction is a type of chemical reaction that involves the exchange of one or more hydrogen ions.
• When diluting Sulphuric acid is added to Lime water the calcium sulfate (CaSO4) and water are formed.
• During the reaction more heat is released because it is a reaction with strong acid and strong base hence also known as an exothermic reaction.
• The free lime is insoluble in water and lime water is also known as calcium hydroxide.
• The major use of calcium sulfate is to produce Plaster of Paris and gypsum.

The correct answer is Energy.

Key Points

Energy:

• Energy, in simple terms, can be defined as the capacity for doing work.
• It can occur in kinetic, potential, electrical, chemical, nuclear, thermal, and other forms.
• The SI Unit of Energy is Joule.
• The name of this international unit is kept in honour of James Prescott Joule, a British physicist whose works contributed to the establishment of the energy concept.
• SI Unit- Joule
• CGS Unit- Erg
• MKS Unit- Joule
• Unit Conversion:
• 1 erg = 10^-7 Joule
• 1 N.m = 1 Joule
• 1 Kg.m²/S² = 1 N.m = 1 Joule
• 1 Calorie = 4.187 Joule
• Kilowatt-hour is the commercial unit of energy.
• 1 kWh = 1kW x 1h = 1000W x 1h = 1000(J/s) x 3600 s = 3.6 x10⁶ J

Additional Information

CONCEPT:

• Plane Mirror: A plane mirror is a mirror with a flat (planar) reflective surface.

The characteristics of an image formed in a plane mirror:

• The image formed by the plane mirror is virtual and erect i.e. image cannot be projected or focused on a screen.

• The distance of the image ‘behind’ the mirror is the same as the distance of the object in front of the mirror.

• The size of the image formed is the same as the size of the object.

• The image is laterally inverted, i.e. left hand appears to be right hand when seen from the plane mirror.

• If the object moves towards (or away from) the mirror at a certain rate, the image also moves towards (or away from) the mirror at the same rate.

EXPLANATION:

Properties of the image formed by a plane mirror are

• It is always Virtual and erect.
• The size of the image is equal to the size of the object and it is laterally inverted.

The scrotum is a part of the male reproductive system. A pair of testes is situated outside the abdominal cavity within a pouch known as the scrotum.

The correct answer is Optical Fiber.

Key Points

About Optical Fiber:

• Optical fiber is a Flexible, Transparent fiber made up of Drawing glass (silica) or plastic. Its diameter is slightly thicker than that of a human hair.
• The principle of the Optical Fiber is based on the Total Internal Reflection which was coined by Daniel Colladon and Jacques Babinet in Paris(France) in the early 1840s.
• These fibers are often used as a means to transmit light over long distances and at higher bandwidths (data transfer rates) than electrical cables and it works in between the two ends of the fiber and finds wide usage in fiber-Optic communications.
• Optical Fibers are used instead of metal wires because it suffers a problem in the long-distance but in Optical fiber, signals travel along with them with less loss. These fibers are immune to Electromagnetic interference.

About Total Internal Reflection:

• Total Internal Reflection(TIR) has the following properties: When the light passes from (Air into Water), the Refracted ray is bent (towards the perpendicular). When the refracted ray passes from (water to air) it is bent from the perpendicular.
• If the angle of the refracted ray which the ray in water encloses with the perpendicular to the surface should be greater than Forty-Eight (48) degrees.
• The Refracted ray will not leave the water at all it will be totally reflected at the surface. The angle which marks the limit where the total reflection starting is called the limiting angle of the medium.

Image of the Total Internal Reflection:

• Not just education, forests, weights and measures, protection of wild animals and birds and administration of justice were also brought under concurrent list through the 42^nd amendment.
• Seventh Schedule of the Indian Constitution provides for various items divided between Union, State, and Concurrent list.

Union List: 100 items on which Parliament has exclusive power to make laws.

State List: 61 items on which States can make and regulate laws.

Concurrent List: 52 items on which both Central and State governments can make laws.

Concept:

Cells: The cell is the basic structural, functional, and biological unit of all known organisms.

• There are different shapes of the cells.
• The size and shape of the cells might be different in different organism.
• Some cells have a nucleus (Eukaryotic cells) while the other does not have a defined nucleus (prokaryotic cells)

In the plant cells, there are different components and organelles for specific functions-

• Cell Wall – It is a rigid layer composed of cellulose. It is the outermost layer of the cell, below this cell membrane is present. The primary function of the cell wall is to protect and provide structural support to the cell.
• Cell Membrane – It is a semi-permeable membrane that helps in regulating and the substance for entry and exit inside and outside the cell.
• Nucleus – It is a vital part of the cell as it contains all the information or DNA of the cell and their heredity information for growth and cell division.
• Vacuole – Most of the part of the plant cell is occupied by the vacuole. It is surrounded by Tonoplast. The vital role of the vacuole is to provide support again the pressure of the cell wall.
• Golgi apparatus – They act like a transport system in the cell, as they transport various molecules to different part of the cell.
• Ribosomes – They are the sites of protein synthesis, also termed as the protein factory of the cell.
• Mitochondrion – They break the complex molecules and produce energy and hence called the powerhouse of the cell.
• Lysosomes – They are termed as suicidal bags as they hold the enzymes that are capable to digest the whole cell itself.

Explanation:

The powerhouse of the cell is Mitochondrion.

The correct answer is Skin.

Key Points

• Skin is the largest organ of the human body, covering the entire external surface. It belongs to the integumentary system and serves as the primary interface between the internal body environment and the external world. Hence, Option B is correct.
• The total surface area of the skin in an average adult human is approximately 20 square feet (roughly 2 square meters).
• It constitutes about 15% of the total body weight. The thickness of the skin varies significantly across the body; for example, it is thinnest on the eyelids (0.5 mm) and thickest on the palms and soles (4 mm).
• The skin is composed of three primary layers: the epidermis (the outermost protective layer), the dermis (containing tough connective tissue, hair follicles, and sweat glands), and the hypodermis (the deeper subcutaneous tissue made of fat and connective tissue).
• Critical functions of the skin include protection against pathogens, regulation of body temperature through thermoregulation, and providing the sense of touch, heat, and cold.

Additional Information

• Lungs: These are the primary organs of the respiratory system in humans and most other animals. Located in the thoracic cavity, they facilitate the exchange of oxygen and carbon dioxide. While they have a massive internal surface area for gas exchange, they are not the largest organ overall. Hence, Option A is incorrect.
• Brain: This is the complex organ that serves as the center of the nervous system. It is contained within the skull (cranium) and controls thought, memory, emotion, and motor skills. The average adult human brain weighs about 1.3 to 1.4 kilograms. Hence, Option C is incorrect.
• Large Intestine: This is the final part of the gastrointestinal tract and the digestive system. Its primary function is to absorb water and salts from the material that has not been digested as food and get rid of any waste products left over. It measures about 1.5 meters (5 feet) in length. Hence, Option D is incorrect.

Important Points

• The Liver is categorized as the largest internal organ and the largest gland in the human body, typically weighing between 1.44 to 1.66 kilograms.
• The Femur, or thigh bone, is the longest, heaviest, and strongest bone in the human body, essential for standing and walking.
• The Stapes, found in the middle ear, is the smallest bone in the human body, measuring only about 3 mm by 2.5 mm.
• The Sartorius muscle is the longest muscle in the human body, stretching from the hip to the inner knee.
• The Small Intestine is the longest part of the digestive system, with an average length of 6 to 7 meters (20 to 22 feet).

Concept:

• Blood clotting or coagulation is the phenomenon in which the liquid consistency of blood transforms into solid at the place of injury.
• This prevents further loss of blood from an injured/open blood vessel.
• It is the major chemical defense against blood loss by forming a semisolid jelly.

 **Explanation:**​

• Ca²⁺ is required for clotting of blood.
• Ca²⁺ ion concentration helps in the activation of proteins in platelets which is essential for the clotting of blood.
• Blood platelets produce thromboplastin that helps blood to clot.
• The action of Ca²⁺ and thromboplastin converts prothrombin into thrombin.

Hence, the correct option is 2.

Additional Information

• The blood clot is formed by a protein named fibrinogen which is present in soluble form in the plasma.
• Fibrinogen is transformed to an insoluble network of fibrous material fibrin, by the clotting mechanism.
• Thrombin catalyzes the conversion reaction of fibrinogen to fibrin.
• The clotting mechanism involves activation, adhesion and aggregation of platelets and deposition of fibrin.