CBSE 12TH BIOLOGY - Online Test
Q1. Homo sapiens arose in Africa and moved across continents and developed into distinct races during
Answer : Option B
Explaination / Solution:
Homo sapiens arose in Africa and moved across continentsand developed into distinct races. During ice age between 75,000-10,000 years ago modern Homo sapiens arose. Pre-historic cave art developed about 18,000 years ago. Agriculture came around 10,000 years back and human settlements started.
Q2. Typically DNA content of about 100000 cells or 1 microgram is required for fingerprinting. If the sample obtained is less it is increased by
Answer : Option C
Explaination / Solution:
Amplification is a mechanism leading to multiple copies of a chromosomal region within a chromosome arm.
The DNA amplification technique of the polymerase chain reaction (PCR) is a laboratory method for creating multiple copies of small segments of DNA.
Q3. Which of the following group of hormones are produced during pregnancy?
Answer : Option A
Explaination / Solution:
Human chorionic gonadotropin (hCG), human placental lactogens (hCL) and relaxin are produced in human females only during pregnancy.
Q4. Modern Homo sapiens arose during ice age between
Answer : Option B
Explaination / Solution:
Homo sapiens arose in Africa and moved across continentsand developed into distinct races. During ice age between 75,000-10,000 years ago modern Homo sapiens arose.
Q5.
Statement I: DNA finger printing is highly reliable method of identification of individual involved in crimes.
Statement II: DNA a fingerprinting is a sure method in solving paternity and maternity disputes.
Statement III: DNA fingerprinting can be used to cure HIV infection.
Answer : Option C
Explaination / Solution:
DNA finger printing is highly reliable method of identification of individual involved in crimes. DNA a fingerprinting is a sure method in solving paternity and maternity disputes.DNA fingerprinting cannot be used to cure HIV infection.
Q6. Parturition occurs due to release of hormone oxytocin that cause
Answer : Option C
Explaination / Solution:
Oxytocin hormone is released by foetal ejection reflex from maternal pituitary gland that causes stronger and stronger uterine contraction that leads to ejection of baby through birth canal.
Q7. Human settlement started around 10, 000 years ago due to starting of
Answer : Option D
Explaination / Solution:
Agriculture came around 10,000 years back and human settlements started. After starting of agriculture, the human civilization started the grows and decline many times.
Q8. The hybridization of probes having radioactive isotopes with various sequence of nitrogen bases with ssVNTR is called
Answer : Option C
Explaination / Solution:
A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization.
Q9. Statement I: During growth of embryo limbs and external genital organ is formed by the ends of 12 weeks.
Statement II: The sex of the developing embryo can be determined using ultrosonography after 3 months of pregnancy.
Statement II: The sex of the developing embryo can be determined using ultrosonography after 3 months of pregnancy.
Answer : Option D
Explaination / Solution:
During growth of embryo limbs and external genital organs is formed by the ends of 12 weeks (3 months). Ultrosonography can be used to know the sex of foetus after this period as genital organs are formed.
Q10. Common origin of man and chimpanzee is best shown by
Answer : Option D
Explaination / Solution:
Common origin of man and chimpanzee is best shown by chromosomes. Both human beings and chimpanzee shows similar kinds of chromosome in terms of number and size.
