What tissue covers the outside of the body and lines organs within the body?

Cytokinesis is the final stage of cell division in which the cytoplasm and organelles are partitioned between two daughter cells, resulting in the formation of two new cells. In animal cells, cytokinesis involves the formation of a contractile ring composed of actin and myosin filaments at the equatorial plane of the cell, which contracts to create a cleavage furrow that pinches the cell membrane inward. This process eventually separates the parent cell into two distinct daughter cells, each containing a complete set of chromosomes and organelles. In plant cells, cytokinesis occurs differently due to the presence of a rigid cell wall. During telophase, the nuclear envelope reforms around the separated chromosomes, and the nucleoli reappear. Chromatin begins to decondense, and the spindle fibers disassemble. As telophase progresses, cytokinesis completes the cell division process, resulting in the formation of two genetically identical daughter cells. Telophase is preceded by anaphase, during which sister chromatids are pulled apart toward opposite poles of the cell by spindle fibers, and followed by cytokinesis, which completes the cell division process initiated during mitosis.

Passive transport is a type of nutrient exchange across a cell membrane that does not require the input of cellular energy (ATP). It relies on the inherent kinetic energy of molecules and the concentration gradient to drive the movement of substances across the membrane. Passive transport mechanisms include diffusion, facilitated diffusion, and osmosis. Diffusion is the spontaneous movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached. Facilitated diffusion involves the facilitated movement of specific molecules (e.g., ions, polar molecules) across the membrane through protein channels or carriers, following their concentration gradient. Osmosis is the passive diffusion of water molecules across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. Unlike passive transport, active transport requires the expenditure of energy (ATP) to transport molecules against their concentration gradient, typically using protein pumps or carriers embedded in the membrane. Passive transport plays a crucial role in nutrient uptake, waste removal, and maintaining osmotic balance in cells and tissues.

A qualitative measurement describes the characteristics or properties of an object or phenomenon without assigning a numerical value or measuring quantity. It focuses on qualitative attributes such as color, shape, texture, size, or appearance rather than quantitative values. In the given options, the statement "George is tall" describes a qualitative attribute (tallness) of an individual (George) without specifying a precise height or measurement. Qualitative measurements are subjective and often based on observational or descriptive criteria rather than precise numerical values. They are commonly used in fields such as biology, sociology, psychology, and anthropology to describe and classify qualitative characteristics, behaviors, or phenomena. In contrast, quantitative measurements involve the determination of numerical values or quantities using standardized units of measurement and precise instrumentation. Examples of quantitative measurements include temperature (°C), length (meters), speed (m/s), volume (liters), mass (grams), and time (seconds).

The immune system is the body's defense mechanism against infectious agents, foreign substances, and abnormal cells. It consists of a complex network of organs, tissues, cells, and molecules that work together to identify, neutralize, and eliminate pathogens (such as bacteria, viruses, fungi, and parasites) and other harmful invaders. The immune system provides both immediate and slower responses tailored to specific infecting agents. Immediate responses, such as inflammation, phagocytosis, and the release of antimicrobial proteins (e.g., interferons), serve to contain and eliminate pathogens rapidly upon their entry into the body. Slower responses, involving adaptive immunity, take several days to develop but provide long-term protection against specific pathogens. Adaptive immunity involves the activation of lymphocytes (B cells and T cells) and the production of antibodies (humoral immunity) or the activation of cytotoxic T cells (cell-mediated immunity) to target and destroy pathogens. The immune system has memory, allowing it to recognize and mount a more rapid and robust response upon re-exposure to previously encountered pathogens. Dysfunction or dysregulation of the immune system can lead to immunodeficiency (increased susceptibility to infections) or autoimmunity (immune reactions against self-antigens), contributing to various diseases and disorders.