CBSE 12TH BIOLOGY - Online Test
Q1. Which article of the Constitution of India specifies that, "it shall be the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers, and wildlife and to have compassion for living creatures."
Answer : Option B
Explaination / Solution:
All the fundamental duties are contained in Art. 51A.
to protect and improve the natural environment including forests, lakes, rivers, and wildlife and to have compassion for living creatures is a fundamental duty listed in constitution of India.
Q2. The Gynoecium of flower having two or more carpel fuse together are called
Answer : Option D
Explaination / Solution:
Gynoecium is the female reproductive part of flower. It consists of single or more than two carpel( pistil). When these carpels are fused together, they are called syncarpous.
Q3. The primary sex organ of human male is
Answer : Option A
Explaination / Solution:
Testis is the primary sex organ in human male as it produce sperm or male gametes without which reproduction is not possible.
Q4. Material used for conducting experiments on genetic traits by Mendel was
Answer : Option B
Explaination / Solution:
Mendel conduct his hybridization experiment on garden pea (Pisumsativum) using different contrasting pair of traits.
Q5. The most common fungal partners of mycorrhiza are ______ species.
Answer : Option C
Explaination / Solution:
Mycorrhiza is symbiotic association between fungus and angiosperms. The most common fungal partners of mycorrhiza are Glomus species.
Q6. The noise level that can cause permanent impairment of hearing ability of human beings :
Answer : Option D
Explaination / Solution:
Noise pollution is a kind of air pollution that may cause permanent impairmentof hearing ability of human beings.
After 150 dB (firecracker) sounds can be felt in the form of shock waves. The pressure difference they cause in the medium can actually be felt by your body. 150 decibels is usually considered enough to burst your eardrums,
Q7. The period from birth to death of an organism represents
Answer : Option D
Explaination / Solution:
The period from Birth of an individual to its natural death is called life span. Different organisms have different life span starting from one day to hundreds of years.
Q8. EtBr fluoresces at the wavelength
Answer : Option B
Explaination / Solution:
Ethidium bromide is an intercalating agent commonly used as a fluorescent tag (nucleic acid stain) in molecular biology laboratories for techniques such as agarose gel electrophoresis. It is commonly abbreviated as "EtBr", which is also an abbreviation for bromoethane. When exposed to ultraviolet light, it will fluoresce with an orange colour, intensifying almost 20-fold after binding to DNA. It fluoresces at the wavelength at 254 nm.
Q9. The first organisms were
Answer : Option D
Explaination / Solution:
The first organisms were chemo heterotrophs. This is because, oxygen was absent on previous earth when organisms have evolved. Chemo heterotrophs can obtain energy from chemicals like sulpher and phosphorus.
Q10. Cry I Ab controls
Answer : Option D
Explaination / Solution:
The Bt toxin is encoded by the cry gene. The cry I AC and cry II Ab control cotton boll worms, while the cry I Ab controls corn borer. Bt gene produces Bt toxin. This toxin provides resistance to plants against lepidopteron, coleopteron and dipterans pests.
