Where is DNA found in a cell?

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12 cm and its sharp image is formed at a distance of 24 cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

Write the number of covalent bonds in the molecule of propane, C₃H₈

The first trophic level in a food chain is always a green plant. Why?

We often observe domestic waste decomposing in the by lanes of our homes. List four ways to make the residents aware that the improper disposal of wastes is harmful to the environment and also for their own health.