Respiration and Circulation — BIOLOGY STD 12 Science — Question

With a neat, labelled diagram, describe the parts of a mature angiosperm embryo sac. Mention the role of synergids.

On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk on such things in public. The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.

1. Why is such awareness programme necessary?
2. What role has the government played in controlling population explosion?
3. When were reproductive health programmes initiated in India?
4. What values did Rohit and his friends show on the occasion?

Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

1. Explain with the help of Griffith's experiment, how the search for genetic material was conducted and what was the conclusion drawn.
2. How did Mac Leod, Mc Carty and Avery establish the Biochemical nature of the socalled. "genetic material' identified by Griffith in his experiments?

Discuss the role of fishery in enhancement of food production.

Anemophily

What is meant by the term 'breed'? What are the objectives of animal breeding?

What are the characteristics of DNA?

With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.

During the explanation of the significance of several breeding techniques, teacher makes a statement about inbreeding depression and suggested a solution for it. Pallavi became very curious about knowing all this and asked certain questions to his teacher.

1. Why is breeding required?
2. What is the significance of improved variety?
3. What is interspecific hybridisation?
4. What values are shown by Pallavi as a science student?