Amphibians are egg/spawn layers: four examples are, frogs, toads, salamanders, and newts.
A complex placenta. Marsupials have a choriovitelline placenta, but it is not as well-developed as the placentas of placental mammals.
Yes, amphibians have highly developed brains.
The placenta is developed during pregnancy from the implantation of a blastocyst. The blastocyst creates the outer layer of the placenta. This continues to developed into two more portions and then develops an outer protective layer. The placenta grows throughout the entire pregnancy.
On what planet? Amphibians are alive and well on Earth.
When Pangaea was in existence, the main animals were reptiles and amphibians. During this time, birds developed also.
Amphibians. Amphibians evolved in the Devonian period, about 400 mya. Adelobasileus, thought to be the ancestor of all modern mammals, lived in the late Triassic, about 225 mya.
No, dinosaurs are more closely related to reptiles than amphibians. Both dinosaurs and reptiles belong to the group called diapsids, which are characterized by having two openings in the skull behind the eye socket. Amphibians, on the other hand, belong to a different group called tetrapods.
Fish, birds, crocodiles, insects, lizards, amphibians, and pretty much anything that isn't a mammal or gives live birth.
Reptiles live on dry land; amphibians live on land as well as in water.
Nobody alive today is "making amphibians". According to scientists, amphibians developed at some point in the Devonian Era, between 400-350 million years ago from fishes through gradual changes. According to creationists, God created amphibians.
Well they have limbs and lungs, which I would consider more complex.
The first fish to develop legs and who mostly developed as the earliest amphibians, being able to live on and as well in water, came about around 370-400 million years ago.