Biology Delhi Set 2 2016-2017 Commerce (English Medium) Class 12 Question Paper Solution

What is "fitness of an individual" according to Darwin?

What is biopiracy?

Suggest a method to ensure an anamnestic response in humans.

State the fate of a pair of autosomes during gamete formation.

Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.

By taking two examples explain how has bio-fortification helped in improving food quality.

Plenty of algal bloom is observed in a pond in your locality.

(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure.

How does the application of cyanobacteria help improve agricultural output?

In a flowering plant a microspore mother cell produces four male gametophytes while a megapore mother cell forms only one female gametophyte. Explain

Describe the structure of a nucleosome.

Mention the evolutionary significance of the Shrews

Mention the evolutionary significance of the Lobefins

Mention the evolutionary significance of the Homo habilis

Mention the evolutionary significance of the Homo erectus

During a medical investigation, an infant was found to possess an extra  chromosome-21. Describe the symptoms the child is likely to develop later in the life.

'in-situ' Conservation can help endangered/threatened species. Justify the statement.

Name and describe any three causes of bio-diversity losses.

Difference between an annual and biennial plants. Provide one example of each.

Describe the structure of a seminiferous tubule.

A number of passengers were severely burnt beyond recognition during a train accident. Name and describe a modern technique that can help hand over the dead to their relatives.

p² + 2pq + q² = 1. Explain this algebraic equation on the basis of Hardy Weinberg's principle.

Explain the role of Restriction endonuclease in Biotechnology

Explain the role of the Gel − electrophoresis in Biotechnology

Explain the role of the Selectable markers in pBR322 in Biotechnology.

Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen.

Write the steps you would suggest to be undertaken to obtain a foreign-gene-product.

Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.

Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.

Explain the importance of "selection" during inbreeding in cattle

A group of youth were having a 'rave party' in an isolated area and was raided by police. Packets of 'smack' and syringes with needles were found littered around.

(a) Why is taking 'smack' considered an abuse?

(b) Write the chemical name of 'smack' and the name of its source plant.

(c) Syringes and needles used by the youth for taking the drug could prove to be very fatal. Why?

Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident's Welfare Association of your locality organized an awareness programme entitled "Bury not burn". They invited you, being a biology student to participate.

(a) How would you justify your arguments that promote burying and discourage burning? (Give two reasons)

(b) With the help of flow charts, one for each practice depict the chain of events that follow.

What is an age-pyramid?

Represent diagrammatically three kinds of age-pyramids for human populations.

Discuss the role of healthy ecosystem services as a pre-requisite for a wide range of economic, environmental and aesthetic goods and services

Read the statement and answer the questions that follow.

A flower of brinjal has 520 ovules in its ovary. However, it produces a fruit with only 480 viable seeds.

(a) What could have prevented the rest of the 40 ovules from maturing into viable seeds? Explain giving a reason.

(b) Describe the development of a dicot embryo in a viable seed.

(c) Why certain angiospermic seed albuminous while others are exalbuminous? Explain.

Name the hormones secreted and write their functions by corpus luteum and placenta (any two).

Name the hormones secreted and write their functions : during Follicular phase and parturition.

Name the stages in a human female where Corpus luteum and placenta co-exist.

Name the stages in a human female where : Corpus luteum temporarily ceases to exist.

Work out a typical Mendelian dihybrid cross and state the law that he derived from it.

How do the observations made during moth collection in pre- and post- industrialized era in England support evolution by Natural Selection?

Explain the phenomenon that is well represented by Darwin's finches other than natural selection.