1. Cell division: This is the most common way for living things to grow. Cells divide and create new cells, increasing the total number of cells in an organism. This process is called mitosis for most cells, and meiosis for specialized cells like gametes (eggs and sperm).

2. Cell enlargement: Cells can also grow in size. This is often coupled with cell division, where newly created cells grow larger before dividing again. This process involves the cell taking in nutrients and building more cellular components like proteins and organelles.

These two processes work together to allow organisms to grow larger and more complex over time.