Fill in the blanks for the following

Fill in the blanks
(i) ----- is a simple gaseous hormone.
(ii) ------ is shedding of leaves, fruits or flowers by a plant
(iii) Plant growth is generally confined to -------- regions and in ----------tissues.
(iv) Cytokinins are synthesised in areas where --------- is occurring.

(i) Ethylene (ii) Abscission
(iii) Apical regions and meristematic tissues (iv) Cell division.