11. Which among the following carries impure blood to human heart?
[A] Pulmonary vein
[B] Vena Cava
[C] Aorta
[D] Pulmonary arteries
Show Answer
Correct Answer: D [Pulmonary arteries]
Notes:
The pulmonary artery carries impure blood to the right and left lungs. The left half of the heart collects and pumps pure (oxygenated) blood from the lungs to all parts of the body.
12. What is the time taken by the rashes to appear on the body of the patient after the Measles attack? (UPSC Prelims 1979).
[A] One day
[B] Four days
[C] Six days
[D] One week
Show Answer
Correct Answer: B [Four days]
Notes:
Measles is a very infectious and potentially serious illness that is caused by a type of virus called paramyxovirus. It is spread from person to person by coughing, sneezing or sometimes kissing. Symptoms will usually begin to show 10 to 14 days after infection with the measles virus. A person with measles is infectious for 2-4 days before the rash appears (when there may be symptoms of fever and tiredness), and for up to 4 days after the rash has appeared.
13. Which one of the following is useful for biological control of pests? (UPSC Prelims 1991)
[A] Honey bees and locusts
[B] Scorpions and spiders
[C] Wasps and birds
[D] Parrots and kites
Show Answer
Correct Answer: B [Scorpions and spiders]
Notes:
Spiders, mites, scorpions, and several related groups are not insects, but belong to the arthropod class Arachnida. About 15 families of spiders are frequently encountered in crops, where they provide benefit as natural control agents.
14. Natural rubber is a plant product which is chemically known by which of the following names? (UPSC Prelims 1992)
[A] Mucilage
[B] Gum
[C] Latex
[D] Resin
Show Answer
Correct Answer: C [Latex]
Notes:
The word latex means only natural rubber. Natural rubber is made from the white sap of some trees such as the Hevea brasiliensis (Euphorbiaceae). Other elastomers, called synthetic rubbers, are made by chemical processes.
15. Which one of the following types of micro-organisms is most widely used in industries? (UPSC Prelims 1998)
[A] Bacteria
[B] Bacteria and fungi
[C] Bacteria and algae
[D] Bacteria, micro-algae and fungi
Show Answer
Correct Answer: D [Bacteria, micro-algae and fungi]
Notes:
Bacteria, micro-algae and fungi are most widely used in industries
16. In which group maximum nutritional diversity is found?
[A] Monera
[B] Plantae
[C] Fungi
[D] Animalia
Show Answer
Correct Answer: A [Monera]
Notes:
The state of Monera has the highest nutritional diversity. Photoautotrophic, chemoautotrophic and heterotrophic have all possible types of nutrition
17. Which bacteria are involved in the oxidation of ammonia into nitrate?
[A] Acetobactor
[B] Nitrococcus
[C] Nitrobacter
[D] Both Nitrococcus and Nitrobacter
Show Answer
Correct Answer: D [Both Nitrococcus and Nitrobacter]
Notes:
The conversion of ammonia into nitrate is a two-step process where ammonia is initially oxidised to nitrite by Nitrosomonas or Nitrococcus, this nitrite is then further oxidised to nitrate by Nitrobacter. This series of conversion is known as nitrification and is an important part of the nitrogen cycle, which is crucial for primary productivity in many ecosystems.
18. Which of the following occurs in Bryophytes?
[A] Great economic value
[B] No value at all
[C] Great ecological importance
[D] A lot of aesthetic value
Show Answer
Correct Answer: C [Great ecological importance]
Notes:
They are called pollution indicators. These prevent soil erosion by running water.
19. A typical gymnospermous plant has 8 chromosomes in leaf cells. What will be the number of chromosomes in the cells of its gametophyte?
[A] 16
[B] 8
[C] 4
[D] 24
Show Answer
Correct Answer: C [4]
Notes:
The gametophytic phase involves the production of male and female gametophytes which are haploid cells. Thus, if the gymnosperm plant has 8 chromosomes then the gametophyte will have 4 chromosomes.
20. Sweet potato is an example of which root?
[A] Conical roots
[B] Fusiform roots
[C] Tuberous roots
[D] Both 1 and 2
Show Answer
Correct Answer: C [Tuberous roots]
Notes:
Sweet potato is an example of Tuberous roots. Tuberous roots have no distinctive shape, appearing thick and fleshy.
