(i) Labour cannot be separated from Labourer : Land and capital can be separated from their owners but labour cannot be separated from a labourer. Labour and labourer are inseparable from each other. The labourer will have to present himself at a place where work is going on. 

For example, it is not possible for a teacher to teach in the school, while staying away at home. Therefore, the worker and his service go together. He cannot sell his labour like land and capital.

(ii) Labour can improve its efficiency : The supply of labour is inelastic in a country at a particular time. It means its supply can neither be increased nor decreased. 

For example, if a country has scarcity of a particular type of workers, its supply cannot be increased within a day, month or year. The supply of labour depends upon the size of population. Population cannot be increased or decreased quickly. Children take time to become workers.

(iii) Labour is perishable : If a worker does not work on a particular day, his labour for that day is wasted. Labour is, thus, perishable. Labour cannot be stored. The labourer has to sell his labour immediately irrespective of the prices (i.e., wages) paid to him. It is because of this feature that labour has a weak bargaining power.