Which one of the following elements is the critical limiting factors in the function of ecosphere because of its irretrievable loss in the ocear:

The relationship between the alga Cladophora and the snail shell on which it grows corresponds to:

The effects of mulches, irrespective their composition, are attributed to:

The major steps of natural pruning is:

Chir pine nursery is:

Bakain (Melia azedarach) utilization of timber: