Subject

Biology

Class

CBSE 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 QuestionsShort Answer Type

11.

How are productivity, gross productivity, net primary productivity and secondary productivity interrelated?

1462 Views

12.

Double fertilization is reported in plants of both, castor and groundnut. However, the mature seeds of groundnut are non-albuminous and castor are albuminous. Explain the Post fertilization events that are responsible for it.

973 Views

Advertisement

13.

Describe the process of Parturition in humans.


Parturition is the process of childbirth or the delivery of the foetus because of vigorous contraction of uterus at the end of the pregnancy which is after the 9 month gestation period. It is induced by a complex neuroendocrine mechanism. Fully developed foetus gives the signal which induces mild uterine contraction called foetal ejection reflex. This triggers results in release of oxytocin from maternal pituitary. The oxytocin results in stronger contractions of the uterine walls and the secretion of more and more oxytocin. The effect of oxytocin and uterine wall contraction leads to stronger contraction which leads to the expulsion of the foetus through the birth canal or parturition.

2263 Views

Advertisement
14.

A teacher wants his/her students to find the genotype of pea plants bearing purple coloured flowers in their school garden. Name and explain the cross that will make it possible.

1059 Views

Advertisement
15.

A DNA segment has a total of 1000 nucleotides, out of which 240 of them are adenine containing nucleotides. How many pyrimidine bases this DNA segment possesses?

531 Views

16.

Draw a diagrammatic sketch of a portion of DNA segment to support your answer.

956 Views

17.

Explain adaptive radiation with the help of a suitable example.

789 Views

18.

A team of students are preparing to participate in the interschool sports meet. During a practice session you find some vials with labels of certain cannabinoids.

(a) Will you report to the authorities? Why?

(b) Name of a plant from which such chemicals are obtained.

(c) Write the effect of these chemicals on human body.

540 Views

Advertisement
19.

Enlist the steps involved in inbreeding of cattle. Suggest two disadvantages of this practice.

611 Views

20.

Choose any three microbes, from the following which are suited for organic farming which is in great demand these days for various reasons. Mention one application of each one chosen.

MycorrhizaMonascusAnabaenaRhizobiumMethanobacteriumTrichoderma.

684 Views

Advertisement