Using various resources such as your school liberary or the internet and discussions with your teacher, trace the evolutionary stages of any one animal, say horse.

Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in case of higher plants and animals on one hand and bacteria on the other hand.

Transgenic organisms are used by humans in various fields, especially to test the action of vaccines before they are used in humans. According to your opinion is there any ethical issue in such experiments? Comment.

Read the following paragraph carefully and answer the following: Tie a stone to one end of a string. Take the other end in your hand and rotate the string so that the stone moves along a circle. As long as we are holding the string, we are pulling the stone towards us i.e. towards the centre of the circle and are appliying a force towards it. The force stops acting on it if we release the string. In this case, the stone will fly off along a straight line which is the tangent to the circle at the position of the stone when the string is released, because that the directionn of its velocity at that instant of time. You may recall a similar activity in which a 5 rupee coin kept on a rotating circular disc flies off the disc along the tangent to the disc. Thus, a force acts on any object moving along a circle and it is directed towards the centre of the circle. This is called the Centripetal force. The impressed force on the same is in which direction?

Read the following paragraph carefully and answer the following: Tie a stone to one end of a string. Take the other end in your hand and rotate the string so that the stone moves along a circle. As long as we are holding the string, we are pulling the stone towards us i.e. towards the centre of the circle and are appliying a force towards it. The force stops acting on it if we release the string. In this case, the stone will fly off along a straight line which is the tangent to the circle at the position of the stone when the string is released, because that the directionn of its velocity at that instant of time. You may recall a similar activity in which a 5 rupee coin kept on a rotating circular disc flies off the disc along the tangent to the disc. Thus, a force acts on any object moving along a circle and it is directed towards the centre of the circle. This is called the Centripetal force. What happens if the string is released?

Read the following paragraph carefully and answer the following: Tie a stone to one end of a string. Take the other end in your hand and rotate the string so that the stone moves along a circle. As long as we are holding the string, we are pulling the stone towards us i.e. towards the centre of the circle and are appliying a force towards it. The force stops acting on it if we release the string. In this case, the stone will fly off along a straight line which is the tangent to the circle at the position of the stone when the string is released, because that the directionn of its velocity at that instant of time. You may recall a similar activity in which a 5 rupee coin kept on a rotating circular disc flies off the disc along the tangent to the disc. Thus, a force acts on any object moving along a circle and it is directed towards the centre of the circle. This is called the Centripetal force. What is centripetal force?

You have been deputed by your school Principal to train local village in the use of biogas plant. With the help of a labelled sketch explain the various parts of the biogas plant.