All Free Biology MCQs with Answers

2091. In which organ RBC are selectively destroyed/ recycled by macrophages?

• A. Spleen
• B. Kidney
• C. Liver
• D. Pancreas

Explanation: The spleen filters blood and its macrophages remove old or damaged RBCs, recycling their iron and other components. The liver also helps clear worn-out RBCs through Kupffer cells, so students may choose it, but the spleen is the main organ associated with selective RBC destruction and recycling.

2092. The flow of lymph is maintained by__________?

• A. Movement of viscera
• B. Breathing movements
• C. Valves
• D. All of these

Explanation: Lymph is moved by skeletal-muscle and visceral movements and by pressure changes during breathing, while valves prevent its backward flow; together these mechanisms maintain one-way lymph movement. Students may choose valves alone, but valves do not actively propel lymph and mainly stop backflow.

2093. Conclusion of Mendels work latter became a_____________?

• A. Scientific hypothesis
• B. Theory
• C. Scientific law
• D. Productive theory

Explanation: Mendel’s repeatedly supported conclusions about segregation and independent assortment became recognised as laws of inheritance because they describe consistent patterns observed in genetic crosses. Theory may be chosen because Mendel’s work explained inheritance, but the standard term for these specific general rules is Mendel’s laws.

2094. Father of genetics?

• A. Morgan
• B. Darwin
• C. Aristotle
• D. Mendal

Explanation: Gregor Mendel is called the father of genetics because his pea-plant experiments established the basic laws of segregation and independent assortment. Students may choose Morgan because he made important discoveries about genes on chromosomes, but he worked after Mendel and is associated with chromosome theory and linkage.

2095. Mendal studied _________ traits of pisum sativum?

• A. Six
• B. Seven
• C. Eight
• D. Nine

Explanation: Mendel selected seven contrasting pairs of traits in Pisum sativum, including seed shape, seed colour and flower position. Students may choose six because some summaries list six visible examples, but the classic Mendelian experiment involved seven pairs.

2096. The character which appears physically in an animal is __________?

• A. Genotype
• B. Phenotype
• C. Heterotype
• D. Morphozygous

Explanation: The phenotype is the observable physical or physiological expression of an organism's genetic makeup, such as height, eye colour, or blood group. The genotype is the allele combination underlying that expression and may not be directly visible. Students may choose genotype because it determines the character, but determination is different from physical appearance.

2097. If two opposite alleles come together, one finding morphological expression masking the other, the fact is described as law of _________ ?

• A. Inheritance
• B. Dominance
• C. Limiting factor
• D. Segregation

Explanation: Mendel's law of dominance describes how, in a heterozygote, one allele can express its trait while masking the expression of the other allele. The masked allele is recessive, but the relationship being described is dominance. Students may choose segregation because it is another Mendelian law, but segregation concerns separation of allele pairs during gamete formation.

2098. The sum of genes in a population is called ________?

• A. Genotype
• B. Karyotype
• C. Gene pool
• D. Lethal gene

Explanation: A gene pool is the complete collection of all genes and their alleles present in a population at a given time. A genotype describes the genetic makeup of one organism, while a karyotype describes its chromosome complement. Students may choose genotype because it also refers to genetic information, but genotype applies to an individual rather than the whole population.

2099. Laws of segregation and dominance were given by ________?

• A. Darwin
• B. Morgan
• C. Mendel
• D. De Vries

Explanation: Gregor Mendel formulated the law of segregation, which states that the two alleles of a gene separate during gamete formation, and the law of dominance, which describes how one allele can mask another in a heterozygote. Students may choose Morgan because he also studied inheritance, but Morgan is mainly associated with gene linkage and crossing over.

2100. Term allele was coined by?

• A. Negalli
• B. Bitson
• C. Dixon
• D. Robert Brown

Explanation: William Bateson coined the term allele for alternative forms of the same gene. Option b appears to misspell Bateson as “Bitson,” but it is the intended name; students may choose Dixon because the unfamiliar names can be confused.