not at first, but into the first trimester it will get hard. Your uterus creates a lining that does not shed; which is called your "wall".
Nothing
Its not hard at all. When in heat they should be able to get pregnant. Sometimes on their first time they don't get pregnant. But that's rare.
Getting pregnant is very hard or very easy depending on how easily your body conceives
Sure.
Constipation usually have other reasons then pregnancy but the only way to be sure if you are pregnant or not is to take a test.
Yes. There is nothing wrong with laughing while you are pregnant!
Yes, a pregnant cat's belly can feel firm or slightly hard due to the growing kittens inside her uterus.
yes
A pregnant cat has a hard belly because the growing kittens inside her uterus cause her abdomen to expand and become firm.
Your stomach gets hard around the 5-6month.
Yes, it is normal for a pregnant cat to have a hard belly as the growing kittens and expanding uterus can cause the abdomen to feel firm.
yes it doesnt do anything to you