No, they are all omnivorous to some extent. Squirrels and gerbils will eat insects if their regular food is scarce - rats are actively predatory and will eat almost anything.
Gerbils live in the dessert and Rats live about anywhere.
yes
Guinea pigs, gerbils, or rats.
yes
Yes averagely
Yes, gerbils can eat lettuce.
Gerbils can eat cauliflower, being herbivores.
Yes, gerbils can eat carrots.
Mice, lemmings, hamsters, Gerbils, muskrat..
Some reptiles do. For an example, a snake could eat a rat or a mouse, but also, animals eat rodents. Owls eat hamsters, gerbils, and guinea pigs. Rats eat mice. Etc.
No - snakes are exclusively meat-eaters. The majority of species eat rodents such as mice, rats and gerbils. Larger species eat rabbits, while the largest of the pythons prey on animals such as antelope.