Some different plants for people usage in the world

 What is a sea cucumber?

A sea cucumber is not a vegetable but a sea animal. It has tough leathery skin. It enjoys lying around on the sea floor in tropical and subtropical regions.

Sea cucumbers look more like long fat sausages with tentacles at one end. These tentacles help them feed themselves. They feed by poking the sticky tentacles around and then placing them one by one into the mouth the action is similar to licking jam or marmalade from your fingers.

Sea cucumbers are slow-moving creatures. To save themselves from being eaten by crabs, fish or starfish, many sea cucumbers produce poison. Some others, when attacked, eject long white sticky threads from their rear ends to enmesh the offender.

Some species do abnormal things such as turning themselves partially inside out when they see danger.

Then they start throwing out their branched respiratory organs, reproductive organs and some intestines. This can really confuse the enemy and give the sea cucumber time to escape. The missing organs are soon replaced by new ones.

How do oysters make pearls?

Oysters belong to a class of molluscs called Bivalvia because of their hinged double shells or valves. Oysters have a soft and sensitive body inside their hinged shells.

When a grain of sand or grit gets inside the shell of an oyster and reaches the soft body, it starts covering the grain with layers of a hard smooth substance called nacre.

This is done to reduce the irritation caused by the grain to the sensitive body of the oyster. A beautiful white silky round pearl is formed when many layers of this substance are produced by it.

To get more pearls, people started deliberately putting a grain of sand or a small bead inside the oysters. The idea succeeded, and more and more pearls could be produced by using this method.

These are called cultured pearls and are the same as natural pearls, the only difference being that the process of producing pearls is artificially or deliberately induced.

The main ingredient of the nacre which makes pearls is aragonite, a calcium carbonate distinguished by its orthorhombic crystalline system, its hardness and its special lustre and gloss.

The colour of pearls varies with the type of mollusc and its environment. Colors can be found in ranges from black to white, as well as cream, gray, blue, yellow, lavender, green and mauve

Which is the largest grass?

The most unusual member of the family of grasses is what we call bamboo! Indeed it does not look like the common variety of grasses we see in the garden or on the moors. Bamboo looks more like a tree or a tall bush.

Bamboo grows at a phenomenal speed of about 41 centimetres a day and can reach a height of 35 meters! The stem of bamboo is hollow and smooth. There are many joints on the stem. There are about five hundred different varieties of bamboo in the world. Most bamboos flower every year, but some varieties bloom only three or four times in a hundred years.

All types of bamboo grow in tropical and subtropical climates – in Asia, South America and Africa. Some tall varieties of bamboo have been successfully planted in Florida and California also.

For ages, bamboo has been one of the most useful plants for people living in tropical areas. It is used in making cots, Chairs, tables, posts, rafts, walking sticks baskets, fishing poles, flutes and similar musical instruments.

People build their entire houses including roofs and floors with bamboo. Some varieties of bamboo are so hard that crude knives are made from them. In China, the inner pulp is used for making special kinds of paper. In Japan hollow bamboo stems are used as water pipes in gardening.

In many countries including India, tender shoots of some bamboo varieties are eaten as vegetables and are used for making pickles. Bamboo no doubt is the most useful grass for mankind.

Why is cork so light?

Cork comes from the outer bark of a tree known as the cork oak tree. Cork has excellent insulating and water-resistant qualities. Its thin-walled cells form a matrix of air pockets and because of this, it is very light in weight. It is much lighter than water and keeps floating on water because water cannot easily penetrate the walls of its cells which remain filled with air.

The cork oak trees are grown extensively in Spain and Portugal and most of the world’s cork supply comes from these places. These trees are tall from six to twelve meters high and can be about one meter in diameter.

To obtain cork the tree should be about twenty years old. The bark of this tree is stripped and the tree is allowed to grow its bark again. After nine years, again another stripping is taken.

 The cork obtained from these first two strippings is not of the best quality. The third and all the subsequent strippings, each after nine years duration for about a hundred years, produce cork of good quality.

The use of cork as a bottle stopper has been popular for a long. It's used for floats and life pressure and going back to its original size when released. Because of this resilience, cork has been used to cushion heavy machinery.

Cork has a long life and does not deteriorate easily. It is tasteless and odorless. Its excellent soundproofing and insulating qualities make it very useful in insulating warehouses, freezers refrigerators and soundproofing rooms.