What smoothens the bone surfaces?

How does an Amoeba obtain its food?

What is osmosis?

Carry out the following osmosis experiment:

Take four peeled potato halves and hollow each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) keep cup A empty

(b) put one teaspoon sugar in cup B

(c) put one teaspoon salt in cup C

(d) put one teaspoon sugar in boiled potato cup D.

Keep this setup for two hours. Then observe the four potato cups and answer the following :

(i) Explain why water gathers in the hollowed portion of B and C?

(ii) Why is potato A necessary for this experiment?

(iii) Explain why water does not gather in the hollowed out portions of A and D.

By which instrument you can see internal structure of onion peel cell?

Do different organisms have different types of basic building units ? Briefly explain.

To what the shape and size of cells are related to?

What constitute the basic building block of the cell?

Can you find out more names of some of the unicellular organisms and fungi, other than given in your book?

Name two single celled animals.

Draw diagram of onion peel as it is seen through microscope.