Cellular transport refers to the movement of substances into and out of cells, which is essential for maintaining homeostasis. This process can occur through various mechanisms, including passive transport, where molecules move along their concentration gradient without energy input, and active transport, which requires energy to move substances against their gradient. There are several types of cellular transport, such as diffusion, osmosis, and endocytosis. Diffusion involves the movement of small molecules, like oxygen and carbon dioxide, while osmosis specifically refers to the movement of water across a semipermeable membrane. Endocytosis allows cells to engulf larger particles or fluids, facilitating nutrient uptake and waste removal.