Most fish taste in what we would call a normal way that is, they have taste buds, the organs which detect flavours, in and around their mouths. But there are some fish, in particular those that live in very dark or muddy waters, which do not feed by sight, as they cannot see their mouth area, but also on other …

They grow from a bed of skin containing Keratin-a horn like substance. This bed lies beneath the top skin and as the nail grows it becomes hard and smooth. There is similarity between human nails and animals claws and hooves.

Clouds are formed when water evaporates from rivers, ponds, oceans, and lakes. The tiny droplets of water cling to particles like (dust, salt, or smoke). The air containing this evaporated water vapour rises and expands at higher altitudes where the air pressure is lower and clouds move with the wind. High cirrus clouds are moved by a jet stream and …

If an astronaut leaves his spacecraft during a journey, he cannot walk about in the ordinary way. There is nothing but empty space. There is not even any gravity to pull him in one particular direction. He can only guide himself by the same means as the spacecraft itself – by rocket propulsion. So when astronauts do leave their spacecraft …

On contact with an allergent, chemical substances are released from mast cells and basophils. The chemical mediators (e.g. histamines) in turn attach themselves on to H-1 receptors to produce allergic effects. Anti-allergen drugs block these chemical mediators. The drugs also produce down regulation of H-1 receptors.

The sun is the driving force in all of the Earth’s processes. It is the sun’s rays that keep our planet warm enough for us to be able to survive, it is the weather’s motor, and provides energy for the most important process of all so far as plants and animals are concerned. The sun provides plants with the energy …

Having a tooth extracted or drilled may not be pleasant but-thanks to anaesthetics-at least it’s not painful. These drugs also prevent pain in surgical operations. We feel pain because electrical signals flash along the nerves in our body from the part that hurts to the brain. Anaesthetics interfere with the nerves so that these pain signals are locked. A general …

This is another term for goose-flesh, because cold or fear causes the skin to look like that of a plucked goose. What happens is that when we are cold or receive a fright or shock, nerves which control the tiny muscles at the roots of the hair are disturbed. As a result, these muscles cause the hair to stand on …

When the sun was born from an immense cloud of gas and dust 4,600 million years ago, it is thought to have been surrounded by a disk of surplus material. Gradually, this disk formed into a number of smaller, cold bodies orbiting the sun. The planets were born. Hence the planets are the left-overs from the birth of the Sun. …

An Italian astronomer Galileo Galilei was the first person to work with telescope. In the beginning of 1609, he disclosed the details about the surface of the sun and the moon, Jupiter’s moon and Saturn’s rings, and discovered many stars too faint to be seen with the naked eye. His observations of the solar system led him to support the …