Cells lining the small intestine arrange into ‘finger-like’ projections to increase surface area. Briefly outline why the cells are arranged like this.

The cells lining the small intestine are arranged into 'finger-like' projections, known as villi, to increase the surface area. This is crucial for the process of digestion and absorption of nutrients.

1. Digestion: The small intestine is where most of the digestion of our food takes place. Enzymes in the small intestine break down the food particles into their simplest forms like glucose, amino acids, and fatty acids.

2. Absorption: After the food has been broken down, it needs to be absorbed into the bloodstream so that it can be transported to different parts of the body.

The 'finger-like' projections increase the surface area of the small intestine, allowing for more nutrients to be absorbed at once. This makes the process of digestion and absorption more efficient.

In addition, each of these villi is covered with even smaller projections called microvilli, further increasing the surface area for absorption.

So, the arrangement of cells in this manner is a perfect example of structure being suited to function in biology.