All Free Biology MCQs with Answers

• A. Polymorphism
• B. Gene linkage
• C. Specializaion
• D. Replication

Explanation: OPTION A: The existence of a single species in more than two morphological forms (individual types) is termed as polymorphism.

• A. Lamark
• B. Darwin
• C. Mendel
• D. Linnaeus

Explanation: According to Lamarck's theory, the modifications an organism acquires during its lifetime can be passed along to its offspring.

• A. Genetic drift
• B. Outbreeding
• C. Inbreeding
• D. Bottleneck

Explanation: The reduction of population size with some specific allele and genotype due to a natural disaster is called the bottleneck effect.

• A. Wing of an insect, wing of a bird
• B. Leg of a dog, leg of a spider
• C. The arm of a human, wing of a bat
• D. All of these

Explanation: Birds and humans both are vertebrates. Both share a common ancestor and have a similar embryonic origin.

• A. They have same organs
• B. They have common ancestors
• C. They have similiar appearance
• D. All of above

Explanation: Evolutionary descent and gene similarity are relatively connected with each other.

• A. Mitochondria contain their own DNA, which is a single circular chromosome
• B. Mitochondria and other plastids multiply by binary fission
• C. Mitochondria have their own ribosomes, which are 70S
• D. None of these

Explanation: The endosymbiotic theory posits that some eukaryotic cell organelles evolved from free-living prokaryotes.

• A. Polymorphism
• B. Gene linkage
• C. Speciation
• D. Replication

Explanation: Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.

• A. Genus
• B. Family
• C. Specie
• D. Community

Explanation: Correct option is C. Species is defined as a group of organisms that consist of similar individuals capable of interbreeding or exchanging…

• A. Wallace
• B. Lamark
• C. Lyell
• D. Darwin

Explanation: The correct option is D. Darwin was the first to propose an objective definition of instincts in terms of animal behavior.

• A. Forelimbs of man and bat
• B. Wings of birds and insects
• C. Darwin's finches
• D. All of above options are correct

Explanation: Wings of birds and insects are examples of convergent evolution because they independently evolved similar structures to adapt to similar…

• A. Fossil record
• B. Common ancestor organisms
• C. Vestigial structures
• D. None of these options are correct

Explanation: Fossils provide solid evidence that organisms from the past are not the same as those found today; fossils show a progression of…

• A. Organisms ranged from simple to complex
• B. One type of organisim give rise to another type of organism
• C. Both A & B
• D. All living things specially created by nature

Explanation: The idea that organisms might evolve through time, with one type of organism giving rise to another type of organism, is an ancient one…

• A. Water
• B. Sedimentary rocks
• C. Igneous rocks
• D. Metamorphic rocks

Explanation: Fossils are predominantly found in sedimentary rocks. These rocks are formed from sediments that accumulate in layers over time, often in…

• A. Increase rapidly
• B. Remains same
• C. Slows Down
• D. Declines

Explanation: When resources become scarce, the population growth of a species tends to slow down or stabilize.

• A. The fastest organism in its environment
• B. The strongest organism in its environment
• C. The organism that survives the longest
• D. The organism that leaves the most viable offspring

Explanation: In evolutionary terms, fitness is defined by an organism's ability to pass on its genes to the next generation, not by traits like speed…

• A. Genetic linkage
• B. Genetic expression
• C. Genetic drift
• D. Gene pool

Explanation: Bottlenecks reduce population size drastically, causing a sharper impact of genetic drift.

• A. Vestigial
• B. Analogous structures
• C. Homologous structures
• D. None of these

Explanation: Structures that were once functional in the past but no longer serve a purpose due to evolutionary adaptations and physiological changes…

• A. High
• B. Moderate
• C. Average
• D. 0

Explanation: Fitness in evolutionary terms is measured by the number of offspring that an individual produces that survive and reproduce themselves.

• A. Homologous organs are functionally different but structurally alike
• B. Examples of homologous structures are arms of humans, forelimbs of cats, and flippers of whales
• C. Examples of analogous structures are wings of bats, birds, and insects
• D. Analogous organs are functionally different but structurally alike

Explanation: The correct answer is the statement that describes analogous organs as being functionally different but structurally alike, which is…

• A. Forelimbs of man and bat
• B. Wings of birds and insects
• C. Darwin's finches
• D. All of the above

Explanation: Despite the different underlying structures, both bird wings and insect wings serve the same purpose of enabling the organisms to achieve…