Yes they can die
Unspayed dogs have a greater chance of getting breast cancer and uterus problems such as pyometra (infection in the uterus). Because of these problems statistics show that generally spayed dogs live longer than unspayed dogs.
Hydrometra in dogs is typically caused by hormonal imbalances, such as prolonged exposure to high levels of estrogen without progesterone. This can lead to the accumulation of fluid in the uterus. Other possible causes include mucometra (accumulation of mucus), cystic endometrial hyperplasia, or pyometra (bacterial infection of the uterus).
Absolutely not the uterus is what holds the baby in the womb.
yes
No
has there been any known cases of a women getting pregnant without a uterus
Yes, a dog would have to push to excrete her puppies from her uterus.
No. The tube do not stretch and will break when the embryo grows. The embryo then dies. The mother will die if this is not taken care of.
No. A uterus is a home for a baby, containing vital nutrients for it.
Yes, dogs eventually die.
Dogs don't 'hatch' ! They are born. They develop within the mother dog's uterus (just as a human baby would inside its mother !).
Fetal development goes on without awareness of the shape of the uterus.