Free Introduction to Biology MCQs with Answers

21. If we accept that birds have wings and that sparrows are birds, then we conclude that sparrows have wings. This is an example of:

• A. Inductive reasoning
• B. Deductive reasoning
• C. Hypothesis
• D. Science

Explanation: Deductive reasoning starts from general statements (all birds have wings) and applies them to specific cases (sparrows) to reach a logical conclusion.

22. Six common bioelements account for what percentage of the total mass in the human body:

• A. 10%
• B. 90%
• C. 99%
• D. 9%

Explanation: The six commonest bioelements (oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus) account for about 99% of the human body's total mass.

23. What is the number of bioelements?

• A. 92
• B. 16
• C. 4
• D. 104

Explanation: Bioelements are the chemical elements that are essential for the structure and function of living organisms. Out of the many elements found in nature, only 16 elements are known to play a direct role in the biological processes of life. These include major elements (like carbon, hydrogen, oxygen, nitrogen), minor elements, and trace elements.

24. Which of the following is not included in biology?

• A. Study of animals
• B. Study of plants
• C. Study of atoms and molecules
• D. Study of bacteria and virus

Explanation: The study of atoms and molecules primarily falls under the field of chemistry, not biology. While biology intersects with chemistry in areas like biochemistry, the core study of atoms and molecules is not considered a direct part of biology.

25. One who deals with living parts of the world and non-living things that affect the living things is:

• A. Ethologist
• B. Embryologist
• C. Biologist
• D. Biotechnologist

Explanation: Biologists study living organisms and their interactions with the environment, including non-living elements that affect them.

26. Second most abundant bioelement:

• A. Hydrogen
• B. Carbon
• C. Magnesium
• D. Oxygen

Explanation: Carbon is the second most abundant bioelement in living organisms, forming the backbone of organic compounds.

27. Which one of the following elements is not found in trace amounts in living bodies?

• A. Zinc
• B. Copper
• C. Calcium
• D. Manganese

Explanation: Calcium is not just found in trace amounts; it is present in larger quantities as it is crucial for bone and teeth formation, muscle contraction, and nerve signaling.

28. 65% of bioelements is:

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

Explanation: Oxygen is the most abundant element in the human body by mass, primarily because it is a major component of water, which makes up a significant portion of body weight.

29. Which organ of a plant is involved in producing the next generation sexually?

• A. Root
• B. Leaf
• C. Stem
• D. Flower

Explanation: Flowers are the reproductive organs of plant where sexual reproduction occurs, leading to the formation of seeds.

30. Very similar, potentially interbreeding organisms are:

• A. Species
• B. Individuals
• C. Biosphere
• D. Population

Explanation: A species is a group of organisms that can potentially interbreed and produce fertile offspring.