Answer:
Pear fruits are gritty in nature due to the presence of the sclereids or the stone cells present in the cavities or the pits insides the fruits.
The real function of the sclereids in the pear fruits has not been fully understood but the hypothesis suggests that they act as a defense mechanism tools to plant giants the herbivores which feed on them.
Also, they support the vascular tissues and provides support and structural strength to the fruit.
Thus, sclereids play an important role in the pear fruit.