All Free Biology MCQs with Answers

1701. A series of hypothesis supported by the results of many tests is called ?

• A. Scientific law
• B. Theory
• C. Data
• D. Deduction

Explanation: A scientific theory is a well-supported explanatory framework built from hypotheses that have survived many tests and observations. Scientific law may be chosen because both are strongly supported by evidence, but a law mainly describes a regular pattern, whereas a theory explains how or why that pattern occurs.

1702. Biological sciences have a set methodology and it is based on ?

• A. Experimental inquiry
• B. Esthetic preference
• C. Philosophical ideas
• D. Imaginations

Explanation: Biological science relies on experimental inquiry, in which observations lead to hypotheses that are tested through controlled evidence and repeatable procedures. Philosophical ideas or imagination can help generate questions, but they cannot replace experimental testing as the basis for scientific knowledge.

1703. An unbroken series of species arranged in ancestors to descendent sequence with each later species having evolved from one that immediately preceded it is called?

• A. Biome
• B. Phyletic lineage
• C. Community
• D. Population

Explanation: A phyletic lineage is a continuous evolutionary sequence in which each species is considered to have descended from the species immediately before it. A population is only a group of organisms of one species in an area, so confusing an evolutionary sequence with a present-day group leads to option d rather than option b.

1704. It is possible to date the rocks by comparing the amount of specific radioactive isotopes they contain. Which of the statement is correct in this respect?

• A. Older sediment layers have equal amount of these radioactive isotopes as that of the young ones
• B. Older sediment layers have less amount of these radioactive isotopes as that of the young ones.
• C. Older sediment layers have greater amount of these radioactive isotopes as that of the young ones.
• D. Older sediment layers did not have these radioactive isotopes

Explanation: Radioactive parent isotopes decay with time, so an older rock generally contains less of the original radioactive isotope than a younger rock formed from the same material. Students may choose option c by thinking that age allows radioactive material to accumulate, but decay reduces the parent isotope instead.

1705. The concept that various organisms dominated this planet during various geological time period and thus placing organisms in a time squence came from the studies by ?

• A. Environmental biologist
• B. Paleontologist
• C. Marine biologist
• D. Social biologist

Explanation: Paleontologists study fossils and the rock layers in which they occur, allowing them to identify which organisms lived during different geological periods. An environmental biologist studies relationships between organisms and their surroundings, so option a is the likely confusion.

1706. A large regional community primarily determined by climate is called ?

• A. Population
• B. Community
• C. Biome
• D. Habitat

Explanation: A biome is a large regional community characterized mainly by its climate and the organisms adapted to that climate, such as a desert or tropical rainforest. A community includes interacting populations in a particular area but is not necessarily a large climate-defined region, so option b is the likely distractor.

1707. Different species of plants and animals living in the same habitat is called?

• A. Population
• B. Community
• C. Biome
• D. Habitat

Explanation: A community consists of populations of different species living and interacting in the same habitat. A population contains members of only one species, so option a is chosen when the word species is overlooked.

1708. Group of living organisms of the same species living in the same place at the same time is called ?

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

Explanation: A population is made up of organisms of the same species living in the same geographical area at the same time. A community includes several different species, so option a results from confusing a population with the broader biological community.

1709. The branch of biology which deals with the study of social behavior and communal life of human beings living in any environment is called ?

• A. Environmental biology
• B. Social biology
• C. Human biology
• D. Both b and c

Explanation: Social biology studies how human beings behave in groups and how communal life is organized within different environments. Students may choose human biology because it also studies humans, but human biology is much broader and is not specifically focused on social behaviour.

1710. The study of fossils is called?

• A. Environmental Biology
• B. Historical biology
• C. Palaeontology
• D. Social biology

Explanation: Palaeontology is the study of fossils, which preserves evidence about organisms that lived in the geological past and helps reconstruct evolutionary history. Students may choose historical biology because fossils provide historical evidence, but palaeontology is the specific scientific discipline.