Hi Gargi
As far as I understand it, the Check Product Stock (renaming to Check Stock) task resource is used to check whether the stock item is available in particular location or sales channel, e.g. a store or for online orders. Alternative items, e.g. different colour, may be returned if the item is out-of-stock.
For the Query Product Stock (renaming to Query Stock) task resource, I believe the intention is to support many different use cases, returning a list of stock levels at different locations and/or stock items depending on specific search criteria. For example, this could be used on a mobile app to display which models for a specific brand are currently in stock.
This is just a very basic example, but hope it helps.
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Dan d'Albuquerque
Individual
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