Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Biology

Explain the interrelationship between organic farming and biofertilizers, with the help of any three suitable examples.

How does the activity of each one of the following help in organic farming?
Cyanobacteria

Answer the following question.
What is an ecological pyramid? Compare the pyramids of energy, biomass, and numbers.

Write any two limitations of ecological pyramids.

'The pyramid of energy is always upright.' Explain

Explain with the help of labelled diagrams, the difference between an upright pyramid of biomass and an inverted pyramid of biomass.

Define ecological pyramids.

Starting from the innermost part, the correct sequence of parts in an ovule are ______.

From the sexually transmitted diseases mentioned below, identify the one which does not specifically affect the sex organs ______.

STD/VD/UTI are ______.

If a hybrid expresses a character, is it called ______.

The allele which is unable to express its effect in the presence of another is called ______.

An allele is dominant if it is expressed in ______.

Which of the following is correct regarding HIV, hepatitis B, gonorrhoea, trichomoniasis?

Which one of the following groups includes sexually transmitted diseases caused by bacteria only?

Confirmatory test for STDs is ______.

Hepatitis B is transmitted through ______.

The common means of transmission of AIDS is ______.

Which of the following STDs are not completely curable?

World AIDS day is ______.