Often, a male dog is protective of the pregnant female dog, usually if he is the "mate." Sometimes dogs, mates of the pregnant dog or not, will act aggressivley towards the female dog, also known as the "bitch."
By mating with a male dog.
Yes.
If the female is trying to get pregnant with a male dog then it will go on the males back but if the female dog is going on the males back while pregnant then it may means that they wanted to have another baby.
Like breed her? Female will usually only allow a male on her when she is in heat.
no but its highly likely
Yes. You can get pregnant no matter how old either one is.
If the male has not been neutered and/or the female has not been spayed, then yes. And unneutered dog can get any unspayed female dog pregnant.
Yes. It is just like how after the first sex, a human can get pregnant.
yes, but can obviously not get her pregnant
Three of four minutes
the male dog acts funny because they know they can not "make anything" with the female dog.
No. Only a male can impregnate a female. No female mammal of any species can get another female pregnant. For mammals that have a "heat" cycle, being in "heat" is required for pregnancy by a male. If such a mammal (a dog for instance) is not in heat or doesn't have a male partner, pregnancy is not possible.