I wouldn't take a chance on feeding parakeets any foods not specifically designed for them without first checking with a petfood supplier, animal health clinic, reputable breeder, or veterinarian.
A lot of work goes into producing petfood which is ideally suitable for the particular pet in question and if you want your pet to be as healthy as possible you should buy a good brand and not feed your pet foods designed for other animals or for humans; discourage friends and visitors from doing so too, and don't leave potentially dangerous substances around where your pet might find them. Medications, cigarette butts, cosmetics and so on, can all cause problems for animals and vet bills for owners.
not all animals eat pears
They can, but probably should not be fed pears.
no no no
yes. sometimes, the male has been known to eat or peck the babies.
yes
because Swedes like to eat pears!
They can eat both, though they tend to enjoy pears more than tomatoes.
Possums are expert climbers, and can use their prehensile tail quite well. They will readily eat pears.
Yes
Yes they can
fruits (pears)
according to nature it is not possible but if it hungry and unable to find his food then it may eat another parakeet