All Free Biology MCQs with Answers

• A. Lipid
• B. Carbohydrate
• C. Mineral
• D. Protein

Explanation: Phytochrome is a chromoprotein. It acts as a photoreceptor in plants. It is sensitive to light in the red and far-red regions.

• A. Long-day plants
• B. Short-day plants Short-Short-day plantsantsday plantsants
• C. Neutral-day plants
• D. None of these

Explanation: It has been found that red light inhibits lowering the short-day plants but promotes lowering in long-day plants, under conditions during…

• A. Leaves
• B. Flower
• C. Stem
• D. Roots

Explanation: Florigen is a systemic signal that initiates flowering in plants. It is synthesized in leaves and transported to the shoot apical meristem…

• A. Forming a spore
• B. Budding
• C. Regeneration
• D. Fission

Explanation: In budding, a new individual develops as an outgrowth or bud on the parent organism.

• A. Parthenogenesis
• B. Parthenocarpy
• C. Regeneration
• D. Budding

Explanation: Reproduction of an egg without fertilization by sperm is termed as Parthenogenesis.

• A. Budding
• B. Cloning
• C. Parthenocarpy
• D. Fission

Explanation: Organisms produced from a single cell by subculturing (cloning) are called clones.

• A. Can be only two boys
• B. Can be only two girls
• C. Cannot be one boy and one girl
• D. Can be one boy and one girl

Explanation: In some cases, more than one egg is produced by the female, and all these eggs are independently fertilized forming two or more zygotes.

• A. Variation
• B. Chances of survival
• C. Genetic monotony
• D. All (A), (B) and (C)

Explanation: Sexual reproduction is important to avoid genetic monotony, as it introduces variability in offspring due to the combination of genetic…

• A. Primary spermatocyte
• B. Spermatogonium
• C. Sertoli cell
• D. Secondary spermatocyte

Explanation: Secondary spermatocyte cell type is haploid and is formed through the first meiotic division of a primary spermatocyte.

• A. Mitosis only
• B. Meiosis only
• C. Both mitosis and meiosis
• D. All (A), (B) and (C) are incorrect

Explanation: Both spermatogenesis and oogenesis involve both mitosis and meiosis. Mitosis is responsible for the production of precursor cells…

• A. Primary spermatocyte
• B. Spermatid
• C. Secondary spermatocyte
• D. Spermatogonium

Explanation: After meiosis, the primary spermatocyte differentiates into two secondary spermatocytes.

• A. Oviparous
• B. Viviparous
• C. Dioecious
• D. Neuter

Explanation: In terrestrial conditions, fertilization is internal. Sperms are lodged in the female body where fertilization occurs.

• A. External
• B. Internal
• C. Self
• D. None of these

Explanation: In terrestrial conditions, internal fertilization is more common. Internal fertilization involves the union of male and female gametes…

• A. Ureter
• B. Vas deferens
• C. Urinary bladder
• D. Urethra

Explanation: The urethra is a duct that serves both the reproductive and excretory systems in males.

• A. A pair of testes
• B. Seminiferous tubules
• C. Male copulatory organ
• D. Both A and C

Explanation: The external male genitalia include the following structures:Penis: The penis is the external organ of the male reproductive system.

• A. 500, 20
• B. 300, 40
• C. 800, 20
• D. 500, 10

Explanation: The human testes contain approximately 800 seminiferous tubules, producing around 1,500 sperm per second, totaling around 20-100 million…

• A. Interstitial fluid
• B. Semen
• C. Amniotic fluid
• D. Both (A) and (B)

Explanation: Semen is a mixture of sperm and fluids from various glands. These glands include the seminal vesicles, prostate gland, and bulbourethral…

• A. 30,000
• B. 200,000
• C. 300,000
• D. 20,000

Explanation: Each ovary is enclosed in a tough protective capsule and contains many follicles.

• A. Ovary
• B. Uterus
• C. Oviduct (Fallopian tube)
• D. Cervix

Explanation: Fertilization of human eggs most often takes place in the oviduct, also known as the Fallopian tube.

• A. Parturition
• B. Menstruation
• C. Ovulation
• D. Implantation

Explanation: Ovulation is the release of a mature egg (ovum) from an ovary. It usually occurs around the middle of the menstrual cycle, roughly two…