Subject

Life Sciences

Class

CNET Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

51.

Aspartic acid (Asp) is specified by the codon GAU and GAC. After mutation, Asp is changed to Alanine represented by GCX, where X may be A, U, C, or G. The reversion of the mutation could only be done with reactive oxygen species. The nature of the mutation is considered to be

  • transition

  • transversion

  • either transition or transversion

  • depurination


52.

A cross is made between two plants with white flowers. All the F1 progeny had red coloured flowers. This is because of

  • complementation

  • recombination

  • translocation

  • reversion


53.

Cladistic classification is based on

  • sequential order in which branches arise from a phylogenetic tree

  • the order of sequence divergence

  • morphological features and skeleton of individuals

  • cellular organization and cytoskeleton


54.

Tautonym is an informal taxonomic designation used for animals referring to

  • same name for genus and species

  • same name for species and subspecies

  • trinomial nomenclature

  • the name of the author for the species


Advertisement
55.

A marine biologist dug up a small animal from the ocean floor. The animal was uniformly segmented with short, stiff appendages and soft, flexible skin. It had a complete digestive system and an open circulatory system but no exoskeleton. Based on this description, the animal appears to be a

  • lancelet

  • roundworm

  • mollusc

  • crustacean


56.

Which of these programs is used to conserve a species facing extinction?

  • Captive breeding

  • Natural resources

  • Sustainable use 

  • Edge effects


57.

A grasshopper population is being assessed by the capture-mark-release-recapture method. On the first day, 100 grasshoppers were captured from a given area in 1 hour time, marked and released. On the next day during recapture, 10 marked and 90 unmarked grasshoppers could be found in the same time period from the same area. What will be the estimated population size in the given area?

  • 80

  • 100

  • 1000

  • 10000


Advertisement

58.

Free-living nitrogen fixers can survive in different ecological niches. Identify the incorrect combination from the following list:

  • Azotobacter - acidic soil

  • Deraxia - alkaline soil

  • Beijernckia - acid soil

  • Frankia - neutral soil


A.

Azotobacter - acidic soil

The incorrect combination is- Azotobacter - acidic soil.


Advertisement
Advertisement
59.

A plot of soil contaminated with diesel oil was inoculated with oyster mushrooms. After 4 weeks, more than 95% of the polycyclic aromatic hydrocarbons had been reduced to non-toxic compounds. This process is called

  • phytoremediation

  • chemoremediation

  • mycoremediation

  • zooremediation


60.

In pre-industrial period in England, peppered moths had light coloration which effectively camouflaged them against light-colored trees and lichens. During industrial revolution, many lichens died out and trees became blackened by soot from factories, and interestingly, dark-colored moths were predominantly seen. This happened due to

  • natural selection of dark coloured moths which were initially present in fewer numbers.

  • new mutation which arose due to environmental pollution

  • macroevolution occurring due to environmental change

  • natural selection of the camouflaging mechanism of the moths


Advertisement