भारत के पूर्वी हिस्से में उड़ीसा नाम का राज्य है। महानदी के मुहाने के आसपास की जमीन बहुत उपजाऊ है – धान के खेत, जंगल और ताजा हरी घास, जिसे वहां के मवेशी भरपेट खाते हैं। बहुत पहले वहां एक महाजन की पत्नी अपने तीन बेटों और बहुओं के साथ रहती थी। सुखी परिवार था और सब लोग आराम से रहते …

One of the most difficult tasks of geology (the science or study of the Earth), has been to establish the age of the Earth. Until about fifty years ago the scientists had little information to help them with this problem. By careful observation they could discover whether one rock was older than another, but the further back they went in …

The male stickleback’s belly turns red at the start of the breeding season in spring. Normally the belly of this small fish is silver-colored, the rest of it varying from brown to green. But when the time comes for him to mate he becomes very active in attracting females with his bright new color. In building the home and rearing …

A river will die when pollution reaches such a level that all the available oxygen is absorbed. This can happen if the oxygen is used up by presence in the water of an excessive number of waste organisms. Large amounts of nitrogen or phosphorus make a river’s oxygen-producing plants grow so rapidly that they become over-crowded and die of exhaustion. …

If the earthworm detects an unfamiliar object next to its skin, the muscles will contract immediately and the body will turn to avoid the object. The worm will also turn in response to heat and, in a lesser degree, to light and sound. Even the heat given out by an ordinary match some inches away, will cause a worm to …

Frogs’ eggs become tadpoles with in two weeks of being laid in the water, but tadpoles may take anything from two months to three years to change completely into frogs. The time taken seems to depend on the environment. Tadpoles will generally develop faster in warmer waters. Also the more advanced species of frog have simplified and shortened the process …

A hermit crab changes its shell when it has grown large enough to need a bigger home. This type of crab has a soft abdomen or tail, which is folded up under the body, but it is not protected by a shell of its own as are most other crabs. Instead, the hermit uses empty snails shells as portable shelters, …

The male bee, or drone, dies when there is no more nectar available from the fields. The reason for this is that, when the workers bees can no longer collect nectar for the hive, the production of honey stops. Deprived of their food the drones rapidly grow weak and are carried from the hive by the workers to die. The …

A cow starts to give milk between the ages of two and two-an-a-half years, after the birth of its first calf. For the first few days the milk is unfit for human consumption and is fed to the calf which is afterwards reared separately. During the milking or lactation period that follows the cow’s yield usually reaches a maximum after …

A chameleon will change color when it senses danger. This remarkable member of the lizard family can change color to match its background or, at least, to become almost unrecognizable. The ranges of colors and patterns of the various species differ widely, but most chameleons can become yellow or cream, green or dark brown. They can also adapt spots either …