Most fish tanks are built in plastics because platic does not break easily.Glass people still use now for their fish tanks at home but i rarely see them,because glass fish tanks can break easily although is transparent
Betta fish can be comfortable in tanks large or small. Large tanks can provide space for your betta, while small tanks keep your betta from being stressed. Whichever kind of tank works for you best is just fine!
A plastic tank designed for use with live fish will be perfectly safe. Aside from safety, plastic tanks differ from glass tanks in their durability (generally greater) and their clarity (generally less). Yes they are. Make sure to buy the tank new because older tanks can have problems with leaks.
The Roman empire had a very large industry making fish tanks, before that, the Chinese had been raising fish in holding tanks for about a thousand years. Before that, people were probably building fish tanks since before we understood how to make fire.