Free Introduction to Biology MCQs with Answers

31. One of the following is regarded as a "dynamic collection of organisms."

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

Explanation: A community is a dynamic collection of different species living together and interacting in a particular area.

32. The distributions of organisms can be studied through:

• A. Ecosystems
• B. Biosphere
• C. Biomes
• D. All these

Explanation: Biomes are large geographical biotic units, a major community of plants and animals with similar life forms and environmental conditions. They are specifically used to study the distribution of organisms across different regions of the world.

33. The first living organism originated about how many years ago?

• A. 3000 Million
• B. 2000 Million
• C. 600 Million
• D. 225 Million

Explanation: Scientific evidence suggests that the earliest life forms appeared around 3 billion years ago.

34. Radioactive isotopes contained by older sediment layers are?

• A. Zero
• B. Equal to the younger sediment layer
• C. Less than the younger sediment layer
• D. Greater than the younger sediment layer

Explanation: Radioactive decay decreases the number of isotopes in older layers compared to younger ones.

35. Total number of species identified so far?

• A. Millions
• B. 30 million
• C. 2.5 million
• D. 3 million

Explanation: So far, scientists have identified and named about 2 to 2.5 million species of plants, animals, fungi, protists, and microorganisms.

36. Total number of known species of animals?

• A. 25%
• B. 53.1%
• C. 19.9%
• D. 17.6%

Explanation: There are nearly 2.5 million species of organisms currently known to science. More than half of these are insects (53.1%), and another 17.6% are vascular plants. Animals other than insects are 19.9% (species), and 9.4% are fungi, algae, protozoa, and various prokaryotes.

37. The species cloned so far:

• A. Sheep
• B. Mice
• C. Cows
• D. All these

Explanation: All these species: sheep, mice, and cows have been successfully cloned, showcasing diverse applications in research and agriculture.

38. Which is true for industrialization?

• A. Has helped mankind to raise the standard of living
• B. Has destroyed our environment
• C. Both A and B
• D. None of these

Explanation: Industrialization has helped mankind to raise the standard of living by providing more goods, services, jobs, and technologies. At the same time, industrialization has destroyed our environment through pollution, deforestation, and climate change. Therefore, both statements A and B are true.

39. Degradation of toxic materials by living organisms is known as:

• A. Bioabsorption
• B. Bioremediation
• C. Cloning
• D. Chemotherapy

Explanation: Bioremediation is the process by which living organisms, such as plants or microbes, break down hazardous substances into less toxic or non-toxic substances, effectively cleaning up the environment.

40. The branch of biology that deals with the organisms living in freshwater bodies is:

• A. Environmental biology
• B. Microbiology
• C. Ecology
• D. Freshwater biology

Explanation: Freshwater biology is the branch of biology that deals with the study of organisms living in freshwater bodies such as rivers, lakes, and ponds. It focuses on the interaction of these organisms with their environment.