Science (English Medium) Class 12 - CBSE Important Questions for Biology

Mention any three characteristics of Neanderthal man that lived in near east and central Asia.

What is ‘biofortification’?

What are methanogens?

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

(a) Plan an experiment and prepare a flow chart of the steps that you would follow to ensure that the seeds are formed only from the desired sets of pollen grains. Name the type of experiment that you carried out.

(b) Write the importance of such experiments

Explain the post-pollination events leading to seed production in angiosperms.

List the different types of pollination depending upon the source of pollen gain.

Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.

Why angiosperm anthers are called dithecous?

Explain the different ways apomictic seeds can develop, Give an example of each.

Mention one advantage of apomictic seeds to farmers.

Draw a labelled mature stage of a dicotyledonous embryo.

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

Describe the structure of its microsporangium.

Explain the events up to double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.

Explain the events up to double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.

Explain the events upto double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.
 

Select the option that shows the correctly identified 'U', 'X', 'Y' and 'Z' in a developing dicot embryo.

Select the option that shows the correctly identified 'U', 'X', 'Y' and 'Z' in a developing dicot embryo.

One of the major approaches of crop improvement programme is Artificial Hybridisation. Explain the steps involved in making sure that only the desired pollen grain pollinate the stigma of a bisexual flower by a plant breeder.