An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre '0' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre '0', principal focus F and height of the image on the diagram.

A student adds a spoon full of powdered sodium hydrogen carbonate to a flask containing ethanoic acid. List two main observations, he must note in his note book, about the reaction that takes place. Also write chemical equation for the reaction.

A student is observing a permanent slide showing sequentially the different stages of asexual reproduction taking place in yeast. Name this process and draw diagrams of what he observes in a proper sequence.

Write the name and structure of an alcohol with four carbon atoms in its molecule.

What are those organisms called which bear both the sex organs in the same individual? Give one example of such organism.