Recall the definition by Robbins , " Economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses'. When we observe this , we shall find some important concepts which comprise the main structure if Economic Science .
  The meaning of the three important fundamentals are as follows :

• ends refers to unlimited human wants . From our own experience , we want many things in life and if one want has been satisfied , it would create another need . For example , if we desire to buy a kancil car and we manage to purchase one , later we would want a bigger , imported car and these wants will continue without an end . So , when there is unlimited wants , we would need to choose between the most urgent need and the less urgent want .
• Scare refers to the wants which are unlimited although the means to satisfy these wants are limited . In other words , these are limited resources . Almost all things that men desire or want are scare .
• Alternatives refers to choices which may be made and involves opportunity cost . Scarce resources can be put to various uses . if we are not able to buy an imported car , then are other alternative cars that we can purchase with our limited income .