Life Processes — Science STD 10 — Question

Prepare a list of five activities that you perform daily in which natural resources can be conserved or energy utilisation can be minimised.

Why detergents are better cleansing agents than soaps? Explain.

When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

1. What are (i) organisms A, and (ii) substance B?
2. What are (i) part C, and (ii) part D, of tooth known as?
3. By what name are the holes E in the tooth known?
4. Name the part F of the tooth.
5. What will happen if organisms A reach part F of the tooth known?

How phototropism does occur in plants?

Describe the process of nutrition in Draw labelled diagrams to show the various steps in the nutrition in Amoeba.

A small part of the shoot of a plant is removed with a sharp knife. When the lower end of this small part of the shoot is buried in moist soil, it gradually develops roots and shoots and grows to become a new plant.

1. What is the name of this method of propagating plants?
2. What care should be taken while removing a small part of the shoot from the parent plant with a knife?
3. Name any two plants which provide us with food directly or indirectly and are grown by this method.
4. Give one advantage of this method of producing new plants.
5. State whether it is a sexual method of reproduction or an asexual method. Why?
6. What special name can be given to the genetically identical new plants produced by this technique?

What are the merits of the modern periodic table of elements?

List two advantages associated with water harvesting at the community level.