If it is a simple shell, it is not a creature. If there are molluscs in it, it is a creature. A simple shell is the outer shell of a mollusk living near the water. It is a kind of calcification. The main component is calcium carbonate, which does not have the basic biological characteristics. Is a shell a creature? A simple shell is a calcification formed by the secretion of a special gland cell of a mollusk to protect the soft part of the body.
The main components of shells are calcium carbonate and organic matter, of which the content of calcium carbonate is about 95%.
The essential difference between biology and non biology is whether there is life. Biology has the following characteristics: cellular structure, metabolism, growth, stress and so on. （BeiKeShiShengWuMa）