Biology – 11 | Solved ExercisesCh-0

Here in this section, solved textbook exercises of Biology-11 are given. At present, Punjab Textbook Boards books are taken and solved. The solutions include all type of questions such as Multiple Choice Questions (MCQs), fill in the blanks and short questions. Long questions have not been solved here. They can be consulted from the textbooks. Here are chapter-wise textbook exercise solutions for Biology-11:

Chapter 01

Chapter 02

Chapter 03

Chapter 04

Chapter 05

Chapter 06

Chapter 07

Chapter 08

Chapter 09

Chapter 10

Chapter 11

Chapter 12

Chapter 13



Textbook Exercise


Q.01: Fill in the blanks.
  1. ____________ is the study of organisms in relation to their environment. (Environmental biology)
  2. The study of organisms living in fresh water bodies like rivers, lakes etc. is called ____________. (Fresh water biology)
  3. ___________ is the branch of biology which deals with the study of social behaviour and communal life of human beings. (Social biology)
  4. In the ___________ body, only six bio-elements accounts for 99% of the total mass. (Human)
  5. All living things and non-living things are formed of simple units called ____________. (Cells)
  6. Various organs in plants and various organ systems in animals are assembled together to form an ____________. (Individual)
  7. A ___________ is a group of organisms of the same species located in the same place at the same time. (Population)
  8. A ___________ is based upon observations. (Hypothesis)
  9. A hypothesis is a result of deductive reasoning or it can be the consequence of _____________ reasoning. (Inductive)
Q.02: Write whether the statement is ‘true’ or ‘false’ and write the correct statement if it is false.
  • Penicillin was discovered by Edward Jenner from a fungus Penicillium. (False)
  • Many diseases such as polio, whooping cough, measles, mumps etc. can be controlled by antibiotics. (True)
  • Exposure to the small pox virus allows the body to develop immunity against cowpox virus. (False)
  • AIDS is caused by HIV and it spreads through sexual contacts, blood transfusion, by contaminated syringe or surgical instruments. (True)
Q.03: Each question has four options. Encircle the correct option:

(i) Which one of the followings is a correct sequence in biological method?

  • (a) Observations – hypothesis – law – theory
  • (b) Observation – hypothesis – deduction – testing of deduction
  • (c) Hypothesis – observations – testing of deduction
  • (d) Law – theory – deduction – observations

(ii) Which one of the followings is employed in treatment of cancer?

  • (a) Antibiotics and vaccination
  • (b) Radiotherapy and chemotherapy
  • (c) Chemotherapy and antibodies
  • (d) All of the above        

(iii) Which one of the followings is not a viral disease? 

  • (a) Cow pox
  • (b) Mumps
  • (c) Tetanus
  • (d) Small pox

(iv) Which one of the followings is not related to cloning?

  • (a) Replacement of the nucleus of zygote by another nucleus of the same organism.
  • (b) Separation of cells of embryo to form more embryos.
  • (c) The individuals resulting have similar genetic makeup.
  • (d) Removal of piece of DNA or gene from the cell, and incorporating another gene or piece of DNA in its place.


  1. b
  2. b
  3. c
  4. d

Q.04: Short Questions:

  1. What do you mean by hypothesis?
  2. How does law differ from theory?
  3. What is deductive reasoning?
  4. Define vaccination.
  5. Write a short note on cloning.


(1) What do you mean by hypothesis?

Hypothesis: “Hypothesis is the tentative explanation of the observations.” It is the logical consequence of observations. Hypothesis is tested by experiments. 

Example: When plasmodium was found in the blood of several malarial patients, it was hypothesized that:

Plasmodium is the cause of malaria.”

(2) How does law differ from theory?


  1. A series of hypotheses supported by the results of many tests is called a theory.
  2. It is less general than scientific laws.
  3. Examples: Cell theory, germ theory of diseases.


  1. Scientific law is a uniform or constant fact of nature. It is, virtually, an irrefutable theory.
  2. It is more general than theories & affords answers to even more complex questions.  
  3. Examples: Hardy-Weinberg law, Mendel’s laws of inheritance. 

(iii) What is deductive reasoning?

Deductive Reasoning: “Deductive reasoning moves from ‘general to specific’. It involves drawing specific conclusion from some general principle/assumptions.” It is a way to formulate a hypothesis.

Example: If we accept that ‘all birds have wings’ (premise#1) and that ‘sparrows are birds’ (premise#2), then we conclude that ‘sparrows have wings’.

(v) Define vaccination.

Vaccination: “Vaccination is the inoculation of weakened or dead microorganism of a disease, or proteins or toxins from the organism, into a healthy person to develop immunity against that disease.” Literally, the word ‘vaccine’ has been derived from Latin word ‘vacca’ meaning ‘cow’. This was first of all used by Edward Jenner in 1795, who inoculated the healthy persons with cow pox lesion to prevent from small pox. Later, Pasteur used this technique against the diseases like anthrax, cholera, rabies.

(iv) Write a short note on cloning.

Cloning: “Cloning is a technology for achieving eugenic aims. It is the production of genetically identical copies of an organism or a cell by asexual reproduction.”

Clone: “A cell or an individual and all its asexually produced offspring are called clone.” All members of a clone are genetically identical except when mutation occurs.

Method of Cloning: In cloning, the nucleus from a fertilized egg is removed and a nucleus from a cell of a fully developed individual is inserted in its place. The altered zygote is then implanted in a suitable womb where it completes its development. The new individual formed in this way, is a genetically identical clone of the individual whose nucleus was used.

Examples: Generally, no normal animal reproduces naturally by cloning. Several insects and many plants do, in some circumstances, whereas few do so regularly.

Q.05: Extensive Questions:

  • Define the following branches of biology: Molecular Biology, Microbiology, Marine Biology, Biotechnology.
  • Discuss briefly phyletic lineage in biological organization.
  • Write notes on the following:

(a) Living world in space and time

(b) Population        (c) Community

  • Explain the biological method for solving a biological problem. How do deductive and inductive reasoning play an important role in it?
  • What is the role of the study of Biology in the welfare of mankind?


(i) Branches of Biology:

  • Molecular Biology: “Molecular biology deals with the study of the structure of organisms, cells and their organelles at molecular level.”
  • Microbiology: “Microbiology is the branch of biology which deals with the study of microorganisms including Bacteria, Viruses, Protozoa and microscopic algae and fungi etc.”
  • Marine Biology: “Marine biology is the study of life in seas and oceans. This includes the study of the marine life and the physical and chemical characteristics of the sea, acting as factors for marine life.”
  • Biotechnology: Biotechnology is the branch of biology which deals with the use of living organisms, systems or processes in manufacturing and service industries.
For answers of questions (ii), (iii), (iv) & (v), consult the textbook.

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