Answer:
The animals that have a hard outer layer like turtles are reptiles.
Step-by-step explanation:
Reptiles, including turtles, have a unique characteristic called a "carapace," which is a hard, bony or cartilaginous shell that covers and protects their bodies. This shell is made up of modified ribs and fused vertebrae, providing a durable and protective structure.
Turtles, specifically, have a two-part shell consisting of a top shell called the "carapace" and a bottom shell called the "plastron." These shells are composed of plates called "scutes" that are made of keratin, a tough protein found in many animal structures like nails and hair.
Reptiles, such as turtles, have evolved this hard outer layer as a defense mechanism against predators. The shell provides protection against physical injuries and acts as a shield for their internal organs.
It's important to note that not all reptiles have a hard outer layer like turtles. For example, snakes and lizards have scales instead of a shell. Nonetheless, turtles are a specific group of reptiles known for their unique and distinctive hard shells.