Strategies for Enhancement in Food Production — BIOLOGY STD 12 Science — Question

What do you understand by Food-Chain?

What is trophoectoderm?

Write about the ancestry and evolution of bat, horse and human on the basis of a comparative study of their forelimbs. What are these limbs categorized as?

OR

What is divergent evolution? Explain taking an example of plants.

OR

Divergent evolution leads to homologous structures. Explain with the help of an example.

What could have triggered mass extinctions of species in the past?

What is restriction enzyme? Explain the process of separation and isolation of DNA fragments using gel electrophoresis technique.

Aman with blood group AB and his wife with blood group o claim a child with blood group O as their son. Justify with the help of Punnett square whether it is possible or not.

Define genetic engineering. Name one natural genetic engineer of plants.

Draw a labelled diagram of male reproductive system.

When and where was the World Summit on sustainable development held? How many countries signed the convention? What was the objective?

'Introducing sex education in school is a good step for providing right information to adolescents'. In context to the statement given above, answer the questions that follow.

1. Which part of the brain controls the sex urge?
2. What are the necessary topics that should be taught in schools, in context of STDs and AIDS.