Many insects have a tough outer shell called an exoskeleton. An exoskeleton protects these insects from harm that may happen to them in the natural world.
Erosion and mixed composition. Wind,rain have a way of mixing and can create crystals
Overheating something can create an entirely new thing like water.
Water combined with intense heat crater has.
Answer:
A. Endocrine
Explanation:
The endocrine system is a collection of glands that produce the hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among all the other things