This is the 11456th most frequent Polish word.
jadalne
Edible.
Here, 'jadalne' is used as an adjective describing the fruits' property of being safe to eat.
Te owoce są jadalne.
These fruits are edible.
In this sentence, 'jadalne' asks about the edibility of mushrooms, used again as an adjective indicating a characteristic.
Czy te grzyby są jadalne?
Are these mushrooms edible?
'Jadalnych' here is the plural form in a declension context, describing the plants' edibility in the context of being discovered.