Atoms and Molecules — Science STD 9 — Question

Growing different crops in the same field in a pre-planned succession, to improve the quality and quantity of the crop yield and maintain the fertility of soil is known as:

Which of the following is not a mixture?

The formula unit mass of Ca₃​(PO₄​)_2​ is :

Cell wall is made up of:

One millionth of a metre is:

Which one of the following is incorrect about tuberculosis?

1. It is caused by Salmonella.
2. It commonly affects lungs.
3. Bacteria release tuberculin toxin.
4. Patient's sputum contains blood.

In angiosperms:

1. Xylem possess vessels.
2. Phloem has sieve tubes and companion.
3. Flowers are reproductive structures.
4. All the above.

The phylum of sedentary animals is:

1. Mollusca.
2. Echinodermata.
3. Porifera.
4. Both (a) and (b).

Three spheres have radii 1cm, 2cm and 3cm, respectively. Which sphere exerts maximum pressure on earth?

To separate ammonium chloride from common salt, we use: