Give reasons ammonia is not collected through downward displacement of water

Ammonia gas is lighter than air and hence collected by the downward displacement of air[V.D. of ammonia=8.5, V.D. of air=14.4]. Ammonia is not collected over water since it is highly soluble in water.

i believe that it is a exoplanet

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary