Free Introduction to Biology MCQs with Answers

101. Element found in only 1% of living bodies:

• A. Oxygen
• B. Carbon
• C. Nitrogen
• D. Phosphorus

Explanation: The correct answer is phosphorus. Phosphorus accounts for about 1% of the human body and plays a crucial role in forming bones, DNA, and ATP, which is vital for energy transfer in cells. On the other hand, oxygen, carbon, and nitrogen are found in much higher concentrations. Oxygen accounts for about 65% of the human body mass, mainly as part of water. Carbon makes up about 18%, serving as the backbone for organic molecules. Nitrogen accounts for about 3% and is essential for proteins and nucleic acids. Therefore, among these options, phosphorus is the element found in about 1% of the human body.

102. Where is insulin formed for human use?

• A. Social Biology
• B. Biotechnology
• C. Molecular Biology
• D. Microbiology

Explanation: The correct answer is biotechnology because it involves the use of living systems and organisms to develop or make products, such as the production of insulin for human use. Insulin is produced by genetically modified bacteria or yeast in a process that falls under the domain of biotechnology. Social biology does not relate to insulin production, as it deals with the social interactions of organisms. Molecular biology is more concerned with the study of the molecular basis of biological activity but doesn't specifically handle the production aspect. Microbiology studies microorganisms, which can be used in biotechnology processes, but microbiology itself is not directly responsible for the production of insulin.

103. Use of living organism systems or processes in manufacturing and service industries is known as what?

• A. Biotechnology
• B. Social Biology
• C. Human Biology
• D. Parasitology

Explanation: The correct answer is biotechnology. Biotechnology is a field that utilizes biological processes, organisms, or systems to create products aimed at enhancing the quality of human life. It merges natural sciences with engineering technologies to apply organisms, cells, their components, and molecular analogues for various products and services.In contrast, options like social biology, human biology, and parasitology focus on specific areas of biology that do not primarily relate to industrial or service applications. Social biology examines social behaviors, human biology studies human beings, and parasitology investigates parasites. None of these disciplines is primarily concerned with manufacturing or providing services.

104. All of the following are different branches of biology except

• A. Geography
• B. Evolution
• C. Paleontology
• D. Genetics

Explanation: The correct answer is geography. Geography is primarily concerned with the study of the Earth, its features, and the human societies spread across it. Unlike the other options listed, it does not focus on biological aspects or processes. Evolution examines how life forms change over generations, paleontology explores historical life forms through fossil records, and genetics looks at heredity and variation in organisms, all of which are integral branches of biology.

105. Living things possess all of the following characteristics except

• A. Can acquire and use energy
• B. Cannot maintain a fairly constant internal environment
• C. Contain genetic characteristics
• D. Adjust to changes in their environment

Explanation: Living things maintain a stable internal condition (homeostasis), such as body temperature or water balance. The statement says they cannot maintain it, which is false, so this is the correct answer.

106. Which level of organization has its own attributes that come into being through the living of a group of the same species?

• A. Community
• B. Tissue
• C. Population
• D. Organ

Explanation: A group of organisms of the same species living together in a given area. They show attributes such as birth rate, death rate, population density, etc. These are emergent properties that individuals alone don't have.

107. The number of rats in a field of rice is an example of a:

• A. Community
• B. Ecosystem
• C. Population
• D. Biosphere

Explanation: A population is a group of individuals of the same species living in a defined area at a given time.

108. Which of these is an example of a micromolecule with a low molecular weight?

• A. Water
• B. Starch
• C. Carbon
• D. Oxygen

Explanation: Water is a very small molecule, has a low molecular mass, and is inorganic.

109. The unit of life is:

• A. An organelle
• B. Atom
• C. Subatomic particle
• D. Cell

Explanation: The correct answer is "cell," as cells are the fundamental units of life that compose all living organisms. Each cell functions independently and is capable of performing vital life processes. The other options are incorrect because:An organelle is a part of a cell, not the basic unit of life.An atom refers to the smallest unit of matter, which is not alive.A subatomic particle refers to components of atoms, which also do not exhibit life.

110. Which of the following shows the CORRECT order of biological levels of organisation fromcomplex to simple?

• A. Spleen → Leucocyte → Mitochondria → Adenine
• B. Mitochondria → Spleen → Leucocyte → Adenine
• C. Mitochondria → Adenine → Leucocyte → Spleen
• D. Spleen → Leucocyte → Adenine → Mitochondria

Explanation: The correct order of biological organization from complex to simple is: Spleen → Leucocyte → Mitochondria → Adenine. The spleen is an organ, which is more complex than a leucocyte, a type of cell. Mitochondria are organelles within cells, and adenine is a nucleotide, a molecular component of DNA and RNA. The other options incorrectly order these structures, either starting with a simpler component or misordering the organelles and molecules.