The correct answer is Curvature of the lens.

Important Points

• Focal length of a lens depends on its curvature and the medium outside the lens.

Additional Information

• The ability of a lens to converge or diverge light rays depends on its focal length.
  • For example, a convex lens of short focal length bends the light rays through large angles, by focussing them closer to the optical centre.
  • Similarly, the concave lens of a very short focal length causes a higher divergence than the one with a longer focal length.
• The degree of convergence or divergence of light rays achieved by a lens is expressed in terms of its power.
  • The power of a lens is defined as the reciprocal of its focal length.

The disease Kala-Azar is caused by the protozoan Leishmania donovani

Leishmania donovani: 

• It is a parasitic protozoan belonging to the class Mastigophora or flagellata.
• It is a human parasite that is dimorphic (i.e. shows two forms) & digenetic in nature
• It causes the disease Kala-azar or Dumdum fever by sand fly (phelobotomus)
• The disease is spread by the bite of infected sand-fly
• It can affect the Skin (Cutaneous Leishmaniasis), the mucous membrane of the mouth, throat, and nose (Mucocutaneous Leishmaniasis), Liver, lymph nodes, spleen, and bone marrow (Visceral Leishmaniasis)
• Symptoms include: Cutaneous Leishmaniasis - Skin ulcers
• Mucocutaneous Leishmaniasis - Ulcers in mouth, throat, and nose, Nosebleed, Difficulty in breathing.
• Visceral Leishmaniasis - Weakness, weight loss, loss of appetite, enlarged spleen, liver, lymph nodes, a decrease in the production of blood cells.

Diagram showing the two different forms of Leishmania donovani

Concept

The javac command in Java compiles a program from a command prompt.

It reads a Java source program from a text file and creates a compiled Java class file.

Syntax

javac filename [options]

For example, to compile a program named Abc.java, use this command:

javac Abc.java

Assertion(A): C ++ is object-oriented programming language: TRUE

Reason:

Object oriented programming is about representing objects in software. Objects are the elements through which we observe the world around us. All objects have identity and behavior.  Object oriented programming develops a program around its data and set well defined interfaces to the data.

• C++ supports the concept of object-oriented programming which are: data abstraction, data encapsulation, inheritance, polymorphism.
• Various language elements are also added to C ++ such as references, templates and exception handling.
• Each C++ program is made up of objects with their accompanying member functions and global functions, which do not belong to any single particular class.

Running, Swimming, Dancing requires some body movement from one place to other.

While, Breathing does not require movable body movement.

Hence, Breathing is the correct answer.

• Zero(0) appended in the beginning of an integer data type, says that variable ‘a’ is explicitly assign a octal constant
• In printf function, %d is used as a conversion specifier for decimal, 42 in octal number will get converted into decimal number; (42)₍₈₎= (4× 8)+2=34