Answer:
1. Biological structure of the human body
The human body is organized in different levels according to their complexity.
The levels are the folowing (increasing complexity).
1. Atom (N, O, C,..)
2. Molecule (Protein, lipids, water...)
3. Organelle (mitochondria, golgi apparatus,...)
4. Cell (blood cells, bone cell,..)
5. Tissue (connective tissue, epithelial tissue,..)
6. Organ (lungs, kidney,..)
7. Organ system (skeletal system, muscuar system,...)
8. Organism (the human body)
Each of the levels is formed by an agrupation of the previous level. For example, cells are formed by a number of organelles, and a group of cells form a tissue.
Cells are the basic units of structure of the body, and there are different types of them.
2. Homeostasis
Homeostasis is a process of the body by which the organism works to maintain a stable internal environment, while adjusting to changes in the external environment.
This process is possible because of the work of both the nervous system and the endocrine system. While the first controles the body's activities and detects the necesity of adjustments, the second regulates the activities by using hormones.
