Science (English Medium) Class 12 - CBSE Important Questions

Explain any four reasons for the dominance of the Congress Party in the first three general elections in India.

Highlight any two major problems faced by the Election Commission of India for holding the first General Election in 1952.

Analysis of any two effects of the Emergency declared in 1975 on the politics of India.

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.

Describe the structure of its microsporangium.

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

Why does endosperm development precede embryo development in angiosperm seeds?

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. 

Women are often blamed for producing female children. Consequently, they are ill-treated and ostracized. How will you address this issue scientifically if you were to conduct an awareness programme to highlight the values involved?

Comment on the role of placenta as an endocrine gland.

Your school has been selected by the Department of Education to organize and host an interschool seminar on “Reproductive Health – Problems and Practices”. However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is “too embarrassing.” Put forth four arguments with appropriate reasons and explanation to justify the topic to be very essential and timely.

Name the group of genes that have been identified in normal cells that could lead to cancer. How do these genes cause cancer?

Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society.

1. “Providing sex education in schools in one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement.
2. List any two ‘indicators’ that indicate a reproductively healthy society.

Indiscrimate diagnostic practices using X-rays etc., should be avoided. Give one reason.