Questions

Let the heights of Cat, Table and Turtle be C, T & R respectively.

From the above given figure,

C + T - R = 170 ......(a)

R + T - C = 130 ......(b)

Adding above eqns (a) & (b), we get

2T = 300

T = 150 cm

Hence, the height of the table is 150 cm.

Hardness can be removed by adding sodium carbonate (washing soda) or by passing the water through an ion-exchange column.

Hardness in water is caused by dissolved magnesium ions and calcium ions. These can get into the water when it comes into contact with limestone and other rocks that contain calcium compounds. This can happen, for example, when rainwater flows over these rocks on its way to a reservoir.

Hardness in water is of two types. They are :

1. Temporary hardness

2. Permanent hardness

1. Temporary hardness:: Temporary hardness is caused by dissolved calcium hydrogen carbonate.

2. Permanent hardness:: Permanent hardness is caused by dissolved calcium sulfate. Unlike temporary hardness, it is not removed by boiling the water.

Part IV of Constitution of India deals with Directive Principles of state Policy.

Species richness is generally lower in the Arctic than at lower latitudes, and richness also tends to decline from the low to high Arctic.Many hypotheses have been advanced to explain the overall decline of biodiversity with increasing latitude, although there is still no consensus about a mechanistic explanation. Abiotic factors include lower available energy and area at high latitudes, and the relatively young age of Arctic ecosystems.