We often think of life developing in the context of an environment, but the environment also develops in the context of life. Considering the early beginnings of the earth, which developed in the context of water and rocks, life changed the context of water. Life, moving to land, changed the soil and the context for other organisms to grow. Life and environment are connected inextricably. The preservation of life on earth depends on the integration of life within its environment. Looking at animals and plants, each is adapted to a specific environment which supports their life and well-being.
Lessons from Nature
"The fiercest and most savage of beasts turns tame and gentle with its young. How tender are lions and tigers with their cubs, how fierce timid doe in protecting her dam!... It is as if parenthood gave them special instincts, which override the normal… Hence if life is to be conserved, and the species to survive, the first necessity is parental defense of the young… So if we study the different forms of life, we find the necessity for two kinds of instinct, of two ways of living; and if we make this assertion of human life, it becomes necessary to study children, because of the effects they have upon adults."
"Behavior is affirmed in each individual by experiences carried out on the environment, and therefore the first task of education is to furnish an environment which will permit and aid the child to develop the functions given him by nature."
The Montessori Prepared Environment
"It is necessary to create surroundings for the child that answer his needs no only from the point of view of his physical health but also from the point of view of his spiritual life. The child must be able to act freely in such an environment. There, he must find motives for constructive activity which corresponds to his developmental needs. He must have contact with and adult who is familiar with the laws governing his life and who does not get in his way by overprotecting him by dictating his abilities, or by forcing him to act without taking his needs into account." 
Who is the child at 3-6 years?
"The environment should give the child the possibility to develop according to the laws of nature."
With the powers of The Absorbent Mind and the Sensitive Periods, the child needs a safe, secure environment within which the child can explore and orient himself to the larger world. The child needs tools that will support his need to order his impressions, perfect his coordination of movement, and his ability to use language for communication. The child needs opportunity to engage in purposeful activity that will support the growth of independence, and a social community of peers that will support the growth of independence. The child must have freedom to follow the natural path of development, along with love, respect, and trust.
Elements of the Casa
Dr. Montessori says that the children are like actors in a living scene, "It ought to be a real house… a set of rooms with a garden of which the children are the masters. They contain not only didactic material… but also a complete equipment for the management of the miniature family." She speaks about the central room for "intellectual work", a sitting room as a parlor where the children amuse themselves with conversation, games, and music. She speaks about the dining room with low cupboards accessible to all the children. She says the plates are always of china, and the tumblers and water bottles of real glass. Knives are always included in the table equipment. The dressing room gives each child their own cupboard or shelf. Dr. Montessori speaks about the child's space:
"There is no limit to the equipment of the "Children's Houses", because the children themselves do everything. They sweep the rooms, dust and wash the furniture, polish the brasses, lay and clear away the table, wash up, sweep and roll up the rugs, wash a few little clothes, and cook eggs. As regards their personal toilet, the children know how to dress and undress themselves. They hand their clothes on little hooks, placed very low so as to be within reach of the child, or else they fold up such articles of clothing, as their little serving aprons, of which they take great care, and lay them inside a cupboard kept for the household linen."
"The child absorbs the environment but only the environment which they experience. His interests are created by your interests, his likes on your likes and his fear on your fear.. The children take everything from their environment, religion, customs, fears. They take their guide of life from what is around them… If there is an interest you want to arouse, put the possibilities in the environment."