The minimum age to obtain one's driverâs license should not be raised to 18 because 16-year-olds have a much more focused mind. If you change the minimum driving age to 18, it will be very little different from 16-year-olds because either way they wouldn't have very much driving experience.
Snails make their own shells.They make it with a muscle called the mantle.The mantle then releases liquid.When the liquid hardens it forms the shell.Later in the snails life t â¦ he mantle releases more liquid and the shell becomes bigger.
The central layer of the shell, called ostracum, has two layers of crystals of the same substance, calcium carbonate. The Hipostracum is below, and the most superficial layer is the periostracum, composed of a lot of proteins. The shell of a land snail can be very different in size and shape depending on the species. Some of them are cone-shaped while others are round. However, all of them have a spiral design, caused by the way land snails produce and growth their shells.