Levels of organization in living things: - Cells: The basic unit of life, responsible for carrying out all the functions necessary for survival. - Tissues: Groups of similar cells that work together to perform a specific function. - Organs: Composed of different tissues, organs have specific functions and work together to form organ systems. - Organ systems: Groups of organs that work together to perform complex functions necessary for the survival of an organism. - Organisms: Individual living beings that can carry out all the basic functions of life.

Types of tissues: - Epithelial tissue: Covers the surfaces of the body, lines organs and cavities, and forms glands. It provides protection, absorption, secretion, and sensory reception. - Connective tissue: Supports and connects different structures of the body. It includes bone, cartilage, blood, adipose tissue, and tendons. - Muscle tissue: Responsible for movement and generating force. There are three types of muscle tissue: skeletal, smooth, and cardiac. - Nervous tissue: Composed of neurons and supporting cells, it is responsible for transmitting and processing information in the body.