the variable skink is a reptile
There are about 58,000 known species with backbones, these include; sharks, mammals, birds, amphibians, reptiles, rays and (some types of) fish.
All turtles are reptiles.
Depends on the species. Three for amphibians and some reptiles, four for mammals and birds. The heart has 4 chambers.
Mammals, reptiles, some fish, and some amphibians.
All toads or any amphibians or reptiles will eat any smaller living thing that will fit in its mouth. It doesn't matter if its the same species or even if it is its own young. Another animal of the same species that is slightly smaller should be fine. Do not house reptiles or amphibians together if their is a large size difference.
Coldblooded vertebrates include the fish, the amphibians and the reptiles. There are a actually fish with lungs, lungfish. Some species of lungfish have more or less working gills, but most species need to breath using their lung(s) even when in the water. Amphibians all have a juvenile water-breathing form, no exceptions to my knowledge. Their adult form has lungs. Reptiles (crocodiles, snakes, lizards, turtles) are the group you are probably looking for. These breath using their lungs.
Caecillians Amphibians; Type of tropical snake and earthworms-look-like
Most reptiles and all amphibians lay eggs. Some reptiles are viviparous.
Mammals, some amphibians, some reptiles, and most birds.
Some species of spiders probably can eat grass, but the vast majority of spiders are strict carnivores, eating insects and (sometimes) small amphibians/fish/reptiles.
Birds, monotremes, most reptiles and amphibians are oviparous.